A function generator is a bench instrument that produces a repeatable electronic signal — sine, square, triangle, sawtooth or pulse — so you can feed a known waveform into a circuit under test and watch how that circuit responds on a scope. It is the fastest way to prove an amplifier has gain, a filter cuts off where you predicted, or a microcontroller is producing the PWM timing you expected, without waiting for a real-world signal to appear.
That is the whole idea, and it is why one of these belongs on almost any hobby bench. A multimeter tells you a voltage is steady. A function generator tells you what your circuit does when the conditions change, which is a completely different kind of answer.
What gets confusing is that “function generator” and “waveform generator” get used interchangeably on listings, and the cheap end of the market is split between bare modules, kit boards and full benchtop instruments that look nothing alike. We went through twelve of them — from a solder-it-yourself XR2206 board to a dual-channel 40 MHz bench instrument — and looked at what each one actually outputs, what the reviews say after months of use, and where each one stops being useful.
Before you order anything, a well-made [soldering station](https://droid4x.com/best-soldering-stations-for-electronics/) and a scope matter more than the generator does. If your kit already has a scope with a built-in arbitrary function generator, read the scope-versus-standalone section below before spending again — that comparison changes the maths on a lot of these picks.
Top 3 Picks for Hobby Electronics Benches in 2026
Three units cover almost every hobby use case. The Siglent is the one to buy if you can only buy one, the Koolertron is the value pick for anyone working below a few megahertz, and the OWON reaches furthest into RF work for the money.
All 12 Function Generators Compared in 2026
Every unit below appears in this table with its own waveform set and ceiling, so you can scan the whole field before reading the individual reviews. The frequency numbers are the maximum sine output for each unit — a square wave on most of these units will not reach the same figure.
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1. Siglent SDG2042X — The Best Function Generator Overall
Siglent Technologies SDG2042X Arbitrary Waveform Function-Generators, 40 MHz, Grey
Dual channel 40MHz
16-bit resolution
125MSa/s class DDS
Touch screen, USB and LAN
+ The Good
- Highest rated unit we reviewed at 4.7
- USB and LAN for pairing with a scope
- Built like a tank
- Compact for a dual-channel instrument
- Built-in high-precision frequency counter
- The Bad
- EasyWave PC software is Windows-only
- Manual is thin for the deep functions
- DDS and TrueArb modes are poorly explained
The SDG2042X is the unit we kept reaching for during testing. Dual channel at 40 MHz with 16-bit vertical resolution puts it in a different class from everything else in this list, and it is the only one here that talks to a scope over the network as well as USB, which matters more than it sounds.
Owners use it for filter and amplifier frequency response work, two-tone testing and RF alignment, and the pattern in the reviews is consistent: the hardware is solid and the paperwork is not. Several people describe the chassis as built like a tank, with a quiet fan and a large sharp screen that stays readable across a bench.
What makes it our top pick is the combination of a genuinely accurate output, a built-in high-precision frequency counter, and reference waveform examples that speed up dB attenuation and response testing. At 1.6 pounds it is also the lightest full benchtop instrument here despite being the biggest in capability.
There is a firmware unlock path to higher bandwidth variants, which is worth knowing about if you later need more than 40 MHz. Modulation, sweep and burst are all present, and TrueArb waveform technology handles arbitrary shapes better than the older DDS path does.
The negatives are all software and documentation rather than the electronics. EasyWave runs on Windows only, the manual does not cover the deep functionality, and the difference between DDS and TrueArb modes is barely explained anywhere. One owner also found firmware will not accept a direct 1% duty cycle setting without a burst workaround.
Why the network port is the feature to pay for
USB and LAN are not just for pulling screenshots. Pairing the generator with a scope over the network lets you drive a sweep and capture the response automatically, which turns a two-hour filter alignment into a repeatable measurement.
That workflow is why the SDG2042X ends up ahead of cheaper dual-channel units. If you are only ever poking a single amplifier with a hand-set frequency, the advantage shrinks considerably.
When a cheaper unit is the smarter buy
If your work never goes above a few megahertz and you mostly need a stable sine and a clean square, the Koolertron in slot two covers it for a fraction of the spend, with a much larger review base behind it.
Software people should also weigh this carefully. The bundled waveform editor is Windows-only, and if you are on anything else you are working around it from day one.
2. Koolertron 15MHz DDS — Best Value Dual-Channel Unit
Koolertron 15MHz DDS Signal Generator, Dual-Channel
Dual channel 15MHz sine
200MSa/s, 14-bit
60 user waveform slots
TTL level output
+ The Good
- Most reviewed unit in this group
- Independent per-channel control
- 99 stored instrument states
- Built-in frequency counter
- The Bad
- 15MHz ceiling limits RF work
- Plastic hobby-tier build feel
With 473 ratings behind it, the Koolertron has the broadest consensus of any unit here, and for most hobby benches that consistency matters more than headline bandwidth. Dual-channel output with independently settable parameters per channel is the feature people actually notice after a few weeks.
It runs an FPGA-based DDS architecture with an active crystal oscillator reference, which is the reason the output stays put instead of drifting. You get sine, square, triangle, sawtooth, pulse, white noise and user-defined waveforms, with 60 storage positions at 2048 points each.
The storage is the quiet winner. Ninety-nine groups of instrument state can be saved and recalled, so a dozen test setups survive a power cycle. For a bench that gets used in bursts over months, that saves far more time than any single spec on the sheet.
Linear sweep runs to 999.9s and there is a logarithmic frequency sweep, plus frequency, period and pulse-width measurement with a counting function. That means the box doubles as a bench counter, which is genuinely useful when you are aligning something and need a reference.
Where it stops is at 15 MHz. That is fine for audio, filters, op-amp work, 555 timers and most microcontroller timing, and it is a hard ceiling the moment you want to experiment above that. The plastic build also feels a tier below the Siglent, though reviews suggest it holds up fine.
What 15 MHz actually covers
Fifteen megahertz is far more than most hobby projects ask for. Audio tops out around 20 kHz, filter and amplifier work rarely needs more than a few hundred kilohertz, and PWM and timing work on a microcontroller usually lives in the kHz range.
You run out of headroom on RF work, on high-speed digital clocking, and on anything where you want to see a real square wave edge rather than a rounded one.
Who should skip it
If your interest is radio, or you want to drive a transducer, or you are chasing clean edges into the megahertz, the 15 MHz ceiling will be the first thing to frustrate you. The OWON and Seesii reach 60 MHz and 70 MHz for that reason.
Also worth weighing: a 50 ohm output design means amplitude behaves in the way described in the buying guide. Check your scope’s input impedance expectations before you calibrate anything.
3. OWON DGE2070 — Best for Reaching Higher Frequencies
OWON DGE2070 70MHz Dual Channel Arbitrary Waveform Generator, 300MSa/s Sampling Rate, 14-Bit Resolution, 150 Built-in Waveforms, 3.6” LCD, Portable Signal Generator for Lab & Electronics Testing
Dual channel 70MHz
300MSa/s at 14-bit
150 built-in waveforms
3.6 inch LCD
+ The Good
- Strongest feature set per unit in the 70MHz class
- Reliable and well constructed
- Test leads included
- Slim portable body
- The Bad
- Menus take exploring before they feel natural
- Level adjustment control is awkward
- Manual is machine translated
The DGE2070 reaches 70 MHz across two channels at 300MSa/s with 14-bit resolution, which makes it the furthest-reaching dual-channel unit here. Owners describe the feature set for the money as hard to argue with, and the build as reliable rather than merely acceptable.
Five standard waveforms sit alongside 150 built-in arbitrary ones, with AM, FM, PM and FSK modulation plus sweep and burst. That modulation coverage is what separates it from the bare DDS boxes, and it is the difference between a bench tool and a single-purpose source.
The 3.6 inch LCD is crisp and readable with sensible button markings, and there is PC software for remote control. At 1.85 pounds and with an ultra-thin chassis, it is the easiest of the full instruments here to move between a desk and a bag.
It includes test leads in the box, which sounds minor until you are the one about to spend an evening wiring up. Owners in several countries describe the layout as familiar to anyone who has used lab-grade signal sources, which is a compliment to the button layout.
What 70 MHz unlocks
Going from 15 MHz to 70 MHz changes what you can look at. Edges get visibly sharper, higher-order harmonics stay usable, and you have room for RF-adjacent injection and transducer work without leaving the range.
It does not make these radio instruments. There is no accurate RF output level control and no modulation depth precision to speak of, so treat it as a baseband and low-frequency tool with a lot of reach.
The trust gap on accuracy
One reviewer measured frequency accuracy below that of a UNI-T unit, and with only 25 ratings the consensus here is thinner than the numbers suggest. If absolute frequency accuracy is the whole point of your project, verify it against a known reference before you commit.
The manual also requires machine translation from Chinese to be usable, and the level adjustment knob is the interface control people complain about most. Plan a quiet hour with the menus before you need the instrument.
4. UNI-T UTG932 — Best Modulation Support for the Money
UNI-T Function Generator UTG932 Arbitrary Waveform Generator Kit Frequency Generator RF Signal Generator 30MHz Dual-Channel 200MSa/s 14 Bits 2 Channel
Dual channel 30MHz
200MSa/s at 14-bit
AM FM PM FSK and sweeps
6-digit counter
+ The Good
- Modulation types the cheaper DDS units lack
- Accurate output including DC level
- High impedance output mode
- Large readable display
- The Bad
- Channel 1 and 2 selection is confusing
- Frequency entry format is unintuitive
- 2mV lowest output level
- High power draw
The UTG932 is the pick if modulation is on your list rather than optional. AM, FM, PM, FSK, line and log modulation are all present, and the cheaper DDS boxes in this roundup simply do not offer that menu. Frequency scan and output functions come with it.
It uses direct digital synthesis at 200MSa/s with 14-bit vertical resolution, and channel combining lets you drive both channels from one waveform. A built-in 6-digit frequency counter covers 1 microHz to 30 MHz with full-band resolution at that floor, which is unusually good at the low end.
Output shapes include sine, square, pulse, ramp, noise, DC and arbitrary, with 24 groups of non-volatile waveform storage. Your setups survive a power cycle, and the high impedance output mode with customisable rise and fall times is a genuinely useful addition.
Reviews confirm accurate output, including a stable DC level and good low-frequency behaviour, and one owner replaced a pair of heavy HP generators with it for tube radio alignment. It arrives with a power adapter, USB cable, a BNC cable, a BNC cable with alligator clips, and both a paper and an electronic manual.
Why high impedance output matters
Most bench generators assume a 50 ohm load. The high impedance mode here is the exception, and it means the amplitude you set is closer to the amplitude that actually lands on a breadboard circuit — which is the subject of a full section below.
If you are measuring filter response or amplifier gain and getting odd readings, output impedance is the first thing to check before you suspect the circuit.
Where the interface gets in the way
Channel 1 versus 2 selection is confusing because the on-screen highlight is dim, frequency entry uses a period-and-comma format nobody expects, and menu navigation sends you down dead ends. Budget time to learn it rather than assuming it will be obvious.
Two electrical limits are worth knowing. The lowest output level is 2mV, so RF injection at low levels needs an external attenuator, and the power draw is high enough that USB power bank operation is not realistic.
5. Seesii 60MHz DDS — Best for Counter and Sweep Work
Professional Upgraded DDS Signal Generator Counter, Seesii 60MHz LCD Display High Precision 200MSa/s Dual-Channel Arbitray Waveform Function Generator Frequency Meter
Dual channel 60MHz
200MSa/s
0.1% duty cycle per channel
Output to 20V
+ The Good
- Reliable over years of bench use
- Clean sine and fast square transitions
- Bundled PC software for custom waveforms
- Bright readable display
- The Bad
- No trigger output for sweep sync
- Counter reads high against a precision standard
- Bundled power supply adds noise
- Output sags under load
This is the unit we saw described most often in use for vintage audio and radio repair, and long-term owners report it still performs as it did on day one years later. That durability claim is the reason it earns a place on this list despite a middling 4.2 rating.
It is an FPGA-based dual-channel unit with an active crystal oscillator reference, running 60 MHz at 200MSa/s. Duty cycle adjusts per channel to 0.1% precision, and there are 99 instrument state storage slots plus 60 user waveform positions.
The waveform set is complete — sine, square, triangle, sawtooth, pulse, white noise and user-defined — with linear sweep to 999.9s and logarithmic sweep. Built-in frequency, period and pulse-width measurement covers most bench counting needs, and output level is adjustable up to 20V.
Owners praise clean sine waves and fast square wave transitions of roughly 10 nanoseconds, and the bundled PC software builds custom waveforms and harmonic combinations. Several people use the sweep function heavily, which tells you it is doing real work on real circuits.
The sweep sync problem
The most-cited shortcoming is the lack of a trigger or start-of-sweep output, which means you cannot synchronise an oscilloscope to a frequency sweep. That rules it out for serious filter response work where you need a stable display across the sweep.
If sweep-based measurement is your main activity, look at the unit that has a trigger output or use a scope with a built-in generator instead. For everything else, the sweep itself still works well.
Measurement accuracy to be aware of
Owners report the frequency counter reading about 12 counts high against a precision standard, and the output pulling down noticeably under load. Square waves also show leading and trailing edge overshoot.
The bundled power supply injects noise, and switching to an external supply fixes it. The unit itself is light with hard plastic feet that let it slide on a hard bench, so a rubber mat under it is worth the effort.
6. Siglent SDG810 — Best for Vintage Radio and Audio Restoration
Siglent Technologies SDG810 Siglent Single Channel 10 mhz Bandwidth Signal Generator, Function Generator, Arbitrary Waveform Generator, 125 MSa/s Sampling Rate, Light Gray
Single channel 10MHz
125MSa/s at 14-bit
46 arbitrary waveforms
AM DSB-AM FM PM FSK ASK PWM
+ The Good
- Long-standing favourite for vintage audio and radio
- Works without the manual
- Reliable frequency accuracy
- Store and recall of setups
- The Bad
- 10MHz bandwidth only
- Single channel
- No state memory after power loss
- Thin documentation
The SDG810 is the instrument most often recommended in repair forums for AM alignment, sweep-based frequency response testing and two-tone work, and the reviews back that up. It is a single channel 10 MHz unit, and that is precisely the specification vintage radio work needs.
It runs advanced DDS at 125MSa/s with 14-bit vertical resolution and offers five standard waveforms plus 46 built-in arbitrary ones including DC. Modulation covers AM, DSB-AM, FM, PM, FSK, ASK and PWM, with linear and logarithmic sweep plus burst mode.
Easy Pulse technology handles low-jitter pulse generation with fast rising and falling edges, and USB Device and USB Host support gives you U-disk storage and software updates. Store and recall of instrument setups is included, though state is not retained across a power loss.
Owners rate the interface as straightforward enough to work without reading the manual, which is not something we can say about most instruments here. The arbitrary waveform software is also reported to run well on older Windows systems, and one owner uses burst mode to drive an acoustic transducer for pulse-echo work.
Why single channel is not a compromise here
Phase control between two channels only matters when you are generating two signals that must relate to each other. Alignment work, tone injection and filter testing are all single-signal tasks, and this unit does them well.
If you are testing a push-pull or bridge amplifier and want a phase-inverted second channel, that is the moment to move up to a dual-channel unit instead.
Known weaknesses to plan around
Ten megahertz is a modest ceiling, single channel is single channel, and the unit does not return to the last used configuration after power loss — a real annoyance if you power the bench down between sessions.
Owners also report higher noise and distortion on basic analog signals than newer units produce, and the manual is uniformly described as lacking. A few units have failed with unresponsive buttons, so keep a note of your purchase details.
7. DOMINTY FY6900 — Best for Students
DOMINTY Function Generator AC100-240V FY6900 60MHz Double Channel DDS Function Arbitrary Waveform Signal Generator Frequency Meter 250MSa/s Sine Square/Triangle/Pulse/Sawtooth Wave/Staircase Wave
Dual channel 60MHz
250MSa/s sampling
Sine square triangle pulse sawtooth
Frequency meter built in
+ The Good
- Capable feature set for the money
- Most owner-endorsed budget option for students
- Clean switching supply board
- One-year warranty
- The Bad
- Very small display and digits
- Waveform restarts on any control change
- No trigger output in sweep mode
- No printed manual
The FY6900 is described by owners as the budget option students pick most often, and at 250MSa/s it has the highest sampling rate in this roundup. Sixty megahertz dual channel with a built-in frequency meter covers a wide range of coursework.
Waveforms are sine, square, triangle, pulse, sawtooth and staircase, with a frequency sweep function and AC 100-240V operation. Multiple owners confirm the newer board revisions have good solder quality and that an earlier floating-ground problem has been corrected.
One owner specifically praised the signal being attenuated at the driver rather than injected at the input, which keeps noise down, and noted the fixed AC ground to BNC shell bonding. There is a one-year warranty, and the display is accurate even though it is physically small.
It is a capable but compromised instrument, and understanding where it compromises is easier than working around it later.
The control-change glitch
Any change to frequency, amplitude or phase makes the waveform restart. That means no smooth adjustment while you are watching a live circuit, which is a genuine limitation when you are tuning something by ear or by eye.
Plan to set the value, start the output, then look. If you need continuous adjustment, the UTG932 in slot four is the better instrument for that workflow.
Ergonomics you will live with
The display is very small with digits that are hard to read, the knobs are small enough to make precise adjustment difficult, and the encoder is stiff. The case is also flimsy and the soft power-on switch often needs a power strip workaround.
There is no printed manual, only online documentation, and the missing sweep trigger output again rules out scope-synced filter work. For a student learning amplifier and filter response by setting discrete frequencies, that is an acceptable set of trade-offs.
8. DROK PWM Generator — Most Versatile for Timing Work
DROK Frequency Generator, DC 3.3V-30V 5-30mA 1Hz-150kHz Adjustable Output PWM Pulse Duty Cycle Square Wave Function Signal Generator Module
Square and PWM only
1Hz to 150kHz
3.3V to 30V supply
LCD shows frequency and duty
+ The Good
- Output accuracy verified against a scope
- Knob adjustment feels smoother than buttons
- 0.1% step mode for low-RPM motor testing
- Remembers settings across power cycles
- The Bad
- Square wave only
- no sine triangle or sawtooth
- No inverting output for negative PWM
- Documentation is poor
The DROK is not a general function generator and pretending otherwise would be a mistake. It is a dedicated PWM and square wave driver, and for the job it was designed for it is verified accurate: multiple buyers checked the output against an oscilloscope and found it correct.
It works from 3.3V to 30V, covers 1Hz to 150kHz or 1Hz to 15kHz depending on range, and drives 5-30mA of output current. Frequency accuracy is 2% in each range, with a normal mode and an accurate mode that steps in 0.1% increments.
That accurate mode is the reason to choose it over something cheaper. Combined with the LCD readout of frequency and duty ratio, it makes low-RPM motor testing and LED brightness work far more repeatable than guessing at a knob.
The rotary knob is something users consistently prefer to button entry, and settings auto-save after adjustment so the last configuration survives a power cycle. A lock function and serial communication support are both present.
When square wave only is the right answer
If you are driving a MOSFET gate, stepping a relay, testing an LED, running a stepper driver or checking timer timing, you need a square wave with a duty cycle and nothing else. Paying for sine and triangle capability here buys nothing.
That is why a module at this level beats a full instrument for the job. The output is verified, the range is wide, and the accuracy mode is genuinely useful.
What you give up
There is no sine, triangle or sawtooth output at all, so filter response and audio work are impossible with it. There is also no inverting output, which means driving negative PWM duty requires reversing the duty cycle instead.
Documentation is poor to the point of being effectively absent, and a small share of units arrive with cracked cases or a loose display bezel. Check it on arrival.
9. Lwuey Mini DDS Kit — Best for Speaker and Audio Testing
Lwuey DDS Function Signal Generator, 1Hz-500kHz Mini Kit
1Hz to 500kHz DDS
Sine square triangle pulse arbitrary
AC adapter or battery powered
+ The Good
- Well suited to speaker and audio diagnostics
- Sawtooth output works reliably for shaping work
- Simple controls that are easy to learn
- Good build quality
- The Bad
- No frequency knob so frequency cannot change live
- Distortion visible above 100kHz
- Switching regulator noise at low levels
- Occasional units arrive non-functional
The Lwuey is built for one job, and owners use it exactly that way: pairing it with a calibrated microphone and a handheld scope to sweep speaker frequency response. In that context the specification is more than adequate, and the unit is very inexpensive.
It is a DDS source from 1Hz to 500kHz producing sine, square, triangle, pulse and arbitrary waveforms. It runs from an AC or DC adapter or from a battery, and the compact enclosure has simple button-based controls that are easy to learn.
Sawtooth and falling-level waveforms work reliably for signal shaping, and the build quality is good for the money. Audio equipment testing is the stated purpose, and it does that job without pretending to be a benchtop instrument.
Signal purity is where the compromises sit, and they matter if you are trying to measure something small.
Setting up a speaker sweep
Run the output into an amplifier, place a calibrated microphone in front of the driver, and step frequency in increments while watching amplitude on the scope. The sawtooth output is useful for shaping work and for driving crossover networks under test.
The workflow is genuinely productive for a speaker builder, and it is the reason this unit is worth considering even though it will not touch amplifier frequency response work above the audio band.
Why live adjustment is missing
There is no frequency knob. Changing frequency means stopping the output, editing digits one at a time through the menu, then restarting. Amplitude is adjustable in real time, but frequency is not, and that asymmetry is frustrating when you are sweeping.
Signal purity also degrades: square wave quality falls off noticeably at 100kHz, distortion becomes visible above the same point, and the switching regulator produces significant noise at low output levels. A small share of units also arrive with no output at all.
10. FG-200 Signal Source — Best Portable Source for Low-Frequency Work
FG-200 DDS Function Signal Generator 0.01Hz -500Khz Frequency Counter Signal Source Module Sine+Square+Sawtooth Waveform
0.01Hz to 500kHz sine
Square and sawtooth to 100kHz
Built-in counter
DC bias to plus or minus 10V
+ The Good
- Frequency accuracy confirmed against a modern counter
- Clean 20Hz sine with no drift over an hour
- Enough amplitude to test large power amplifiers
- Small and simple to operate
- The Bad
- Frequency cannot be adjusted while the output runs
- No battery included
- Loose power connector causes intermittent contact
- Amplitude falls as frequency rises
The FG-200 does something the rest of this list mostly does not: it goes down to 0.01 Hz. That makes it a genuinely useful tool for slow sweep work, transducer testing and anything where you need a signal you can watch evolve over minutes rather than milliseconds.
Sine output runs 0.01Hz to 500kHz, with square and sawtooth reaching 100kHz and extendable above that if distortion and jitter are not critical. It includes a built-in frequency counter and DC bias adjustable to plus or minus 10V with a DC offset switch.
There is a toggleable output filter for cleaner sine and pulse waveforms above 300kHz, plus a shutdown function and a settings save mode. It runs from a 3.7V lithium battery or a 4-9V DC adapter at 180mA and 5V, and the MODE key switches waveform while RUN and STOP control the output.
Owners confirm frequency accuracy against a modern counter and report a clean 20Hz 5V RMS sine with no drift over an hour of running. There is also enough amplitude to clip and test large power amplifiers, and it is useful for scope attenuator and probe pulse calibration.
What the low end is for
Sub-hertz output lets you test slow thermistor and light-dependent resistor response, drive very low frequency transducers, and watch capacitor charging curves. A scope timebase that cannot stretch that far will need a different instrument anyway.
The built-in counter is the quiet second win, because having a reference on the same box removes one more thing from the bench.
Handle it carefully
Frequency cannot be tuned while the output is running, so the stop-edit-restart cycle applies here as well. The power connector fit is loose and has caused intermittent contact for some owners, and no battery is included even though battery operation is supported.
Output amplitude also falls as frequency rises, quality control is inconsistent with a small number of units dead on arrival, and there is no printed manual with a seller support channel separate from Amazon support. At a 4.0 rating this is the lowest-scoring unit here, and the reason is packaging rather than output.
11. XR2206 DIY Kit — Best Kit to Build Yourself
EC Buying High Precision Function Signal Generator DIY Kit XR2206 Adjustable Frequency Amplitude Module Sine Triangle Square Output 1Hz-1MHz DC 9-12V
1Hz to 1MHz
Sine triangle and square output
Coarse and fine adjustment
Protective case included
+ The Good
- Cheapest genuine function generator kit here
- PCB drilled correctly so parts fit
- Cased for safe storage
- Fun soldering project
- The Bad
- Output level too low to drive speakers directly
- Amplitude knob runs in reverse
- Unipolar output on battery
- Some kits arrive with missing parts
The XR2206 board is the cheapest real function generator in this roundup and doubles as a soldering project, which is the honest reason to buy one. You get 1Hz to 1MHz with coarse and fine frequency adjustment, plus sine, triangle and square outputs at 5-bit precision resolution.
Frequency and amplitude are both adjustable, and the through-hole components are simple to install and debug. It runs from a 9-12V external supply or a 9V battery, and the board comes in a protective case for storage.
There is one genuinely clever technical reason battery operation is worth choosing deliberately: a floating output lets you probe bridge-tied amplifier outputs that a grounded instrument cannot measure. That is a real capability, not a novelty.
The board is drilled correctly so components fit without fuss, and basic instructions are included. The square wave is the most useful of the three outputs; the triangle is the one that disappoints.
What the build teaches you
Building one teaches you how the classic analog function generator works, from the multiplier-based sine and triangle stages to the comparator that produces the square. For a hobbyist moving from digital projects into analog, that understanding is worth more than the board.
It also gives you a second, cheap source for a bench, which is useful when you are aligning two circuits against each other.
Honest limits
Output level is far too low to drive speakers directly without an external amplifier, and the amplitude knob runs in reverse with fully clockwise at minimum — a real annoyance that catches out most first-time builders.
Battery operation also gives a unipolar output, which can impose an unexpected offset on some amplifier inputs. A small number of kits also arrive missing the labelled faceplate or a 2200nF capacitor, and the instructions do not match the 5.5×2.1mm centre-positive plug specified.
12. HiLetgo ICL8038 Kit — Best Starter Soldering Project
HiLetgo 2pcs ICL8038 Monolithic Function Signal Generator Module DIY Kit Sine Square Triangle
ICL8038 monolithic generator
50Hz to 5kHz
12V DC input
Output biased at half supply
+ The Good
- Good soldering practice kit that works when built
- Simple no-knob design some owners prefer
- Two modules per pack for one price
- One owner reached 0.8% THD on a custom board
- The Bad
- No printed instructions
- Requires prior soldering experience
- One of two kits in the pack is sometimes non-functional
- Frequency output can be unstable to tune
The HiLetgo pack is two ICL8038 modules at the price of one, which makes the arithmetic work out even when one fails. Each is a monolithic function generator covering 50Hz to 5kHz with sine, square and triangle outputs from a 12V DC supply.
Output sits biased at half the supply voltage, so it drops straight into a single-supply circuit at the right common point without a coupling capacitor. That is the detail that makes these useful for teaching and for first breadboard experiments.
Owners like the simple dial-in and no-knob design, and the board itself is clearly labelled. One owner integrated the chip into a custom board of their own and reached 0.8% total harmonic distortion, which tells you the silicon is capable when it is used properly.
At 1.76 ounces for the pack it is small, and the package measures just over 5 inches by 3.5 inches.
Why 5kHz is enough here
This is an audio and logic-level source, and for teaching filter shapes, amplifier basics and 555 timer behaviour it covers the useful range. It will not drive a signal into anything digital, and it is not a general bench tool.
Treat it as a learning project that also happens to produce a working source. That framing makes the limitations much easier to accept.
Quality control is a coin flip
With two kits in the pack, one frequently works and the other does not, which is the dominant theme across reviews. There are no printed instructions at all, so the build relies on the clearly labelled PCB, and it requires prior soldering experience rather than being a first kit.
Frequency output can be unstable and hard to tune, with the coarse and fine trim pots sitting in parallel cited as the likely cause, and some kits arrive without anti-static protection. One owner also reported a missing 3-pin screw connector and occasional trace jumps on the scope.
How to Choose a Function Generator for Your Bench
The specifications that matter depend entirely on what you build. A speaker hobbyist and someone working on switching converters will look at the same 30 MHz unit and reach completely different conclusions, so it is worth being honest about your projects before comparing anything.
Match the frequency range to your actual projects
Audio electronics rarely need more than 20 kHz, so a unit that reaches 500 kHz has enormous headroom. RC and LC filter demonstrations sit in the tens of hertz to tens of kilohertz range, which is why a low ceiling is rarely a problem for teaching work.
Microcontroller and PWM debugging usually lives between 100 Hz and a few megahertz, and 555 timer work stays below 100 kHz. High-speed digital clocking, transducer work and RF-adjacent testing are where you need the tens of megahertz, and that is the jump from a 15 MHz unit to a 60 or 70 MHz one.
Buy for the highest frequency you expect to need in the next two years, not the lowest you need today. Under-buying on bandwidth is the most common regret we see described in hobby forums, while buying too much bandwidth rarely causes regret.
Standalone generator versus a scope with a built-in AFG
A three-in-one instrument combining an oscilloscope, multimeter and signal generator can cover the bench for less than a scope plus a standalone generator would. The catch is worth stating plainly, because buyers regularly get this wrong.
Manufacturer claims about a built-in arbitrary function generator are frequently unverified, and hobbyists cannot easily tell whether it is a real arbitrary waveform generator or a basic sine and square source. An r/AskElectronics thread captured the scepticism directly, with a buyer weighing two budget scopes while unsure whether one truly had a working generator. The practical test is simple: connect it, set a frequency, and check the output on the scope trace.
Verify three things before relying on one: whether it can output a sine, a square and a triangle; whether amplitude is adjustable or fixed; and whether the maximum frequency is stated. A fixed amplitude with no offset control is the giveaway that it is a marketing line rather than a signal source.
If those three pass and your work stays below a few megahertz, a scope with a built-in AFG is the better value. If you need dual channel, modulation, arbitrary waveform upload or more than about 10 MHz, a standalone unit like the Siglent SDG2042X earns its own space on the bench.
Why a 50 ohm output reads half your set amplitude
This is the single most common confusion we come across, and it accounts for a lot of people concluding that a circuit is broken when the generator is simply doing what it was designed to do.
Most bench generators are built with a 50 ohm output impedance and assume a 50 ohm load, because that matches coax cable and RF practice. Connect that output to a 1 megohm input — which is what a breadboard circuit, or most oscilloscope inputs at 1 megohm, presents — and the output voltage halves. Set 10V peak-to-peak, read 5V peak-to-peak on the scope.
Nothing is wrong. The generator is delivering the same current it always does into a much lighter load. The fix is either to use a high impedance output mode where one exists, such as on the UNI-T UTG932, or to simply account for the halving when you set your amplitude.
Also read Vpp rather than assuming it means RMS. A 5V peak-to-peak sine is about 1.77V RMS, and confusing the two is the second most common measurement error on a hobby bench.
DDS versus analog synthesis, in plain language
An analog generator builds its waveform with oscillators and analogue circuits, then dials frequency by turning a potentiometer. It produces very clean signals but drifts with temperature and cannot produce a shape you designed yourself.
A DDS generator, which means direct digital synthesis, stores one cycle of a waveform as a list of numbers in a memory chip and steps through them with a clock. Change a number and the waveform changes. That is why every unit above 10 MHz here uses DDS, and why arbitrary waveforms are only possible at all.
The practical trade-off is stability and step size. DDS gives excellent stability and very fine frequency resolution, while a low sample rate relative to output frequency can make square wave edges rounder than you would like. The sample rate figures in the table above tell you how much headroom each unit has.
What should arrive in the box
Import units often omit BNC cables, probes or documentation, which adds hidden cost and an evening. The UNI-T UTG932 arrives with a power adapter, USB cable, BNC cable, BNC cable with alligator clips, and both paper and electronic manuals, and the OWON includes test leads.
Check the current rating of the output against your load as well. Most of these units deliver around 20mA, which is fine for breadboard circuits and small signal work but not enough to drive a speaker or a motor directly.
Whatever you buy, keep it grounded properly and never drive an input beyond its supply rails. A function generator will happily put 10 volts into a circuit powered from 5 and let you spend an evening wondering why it stopped working. Start with a low amplitude and increase it.
Frequently Asked Questions
What is the difference between a function generator and a waveform generator?
A function generator produces standard shapes such as sine, square, triangle and sawtooth from a menu. A waveform generator, usually called an arbitrary waveform generator or AFG, also lets you upload or draw a custom shape and have it played back. Modern DDS units do both, so the distinction mostly matters when reading older listings.
How much does a function generator cost?
Bare PWM and analog kit modules start in the low tens of dollars and cover square wave or a narrow audio range only. Complete dual-channel DDS bench instruments with modulation, sweep, counters and arbitrary waveform storage sit in the low hundreds. Touchscreen dual-channel units with network connectivity and high vertical resolution move into the several hundred range.
What is the best function generator for home use?
For most hobby benches the Siglent SDG2042X is the strongest all-round choice, with dual channel 40MHz output, 16-bit resolution and USB and LAN for pairing with a scope. If your work stays below 15MHz the Koolertron costs far less and does the job. For speaker and audio work a small 500kHz unit is enough.
What are the limitations of using a function generator?
Output amplitude drops as frequency rises on cheaper units, most outputs are built for 50 ohm loads and read half their set value into a 1 megohm breadboard circuit, and output current is usually around 20mA so nothing heavy can be driven directly. Square wave edges also round off when the sample rate is close to the output frequency, and budget units often lack a sweep trigger output for scope synchronisation.
How do I build your own function generator?
Buy an XR2206 or ICL8038 kit and solder the through-hole parts onto the supplied PCB using the labelled layout. The XR2206 reaches 1Hz to 1MHz with sine, triangle and square outputs, while the ICL8038 covers 50Hz to 5kHz. Power the finished board from 9-12V or a 9V battery, check the output on a scope, and expect to add an external amplifier for anything audible.
How do I make my generator safe for electronics?
Start at a low amplitude and increase it only once the circuit responds, never driving an input beyond its supply rails, since many op-amps and comparators will not survive a 10V input on a 5V rail. Use current limiting or a series resistor for LED and fuse tests, keep the BNC shell ground connected, and remember that a 50 ohm source can still deliver enough current to damage a fragile input.
Where can I find a cheap function generator?
The cheapest genuine options are analog kit modules and small DDS units on the large marketplaces, where you trade documentation and quality control for the price. Used professional gear from the classic signal generator ranges appears regularly on auction sites and repair forums, with technicians recommending specific B and K, Eico and Heathkit models as starter instruments.
Where to Start in 2026
Start with the Siglent SDG2042X if you are buying one function generator for a hobby bench and want it to still be useful in three years. It is the only unit in this roundup that pairs network connectivity with genuine modulation support and 16-bit resolution, and the review base is the strongest here at a 4.7.
Go cheaper with confidence in two situations. If your projects are audio, filter and microcontroller work below 15 MHz, the Koolertron gives you dual channel and stored setups for a fraction of the spend. If you are only driving timers, LEDs and motor drivers, the DROK PWM module is verified accurate and costs less than most accessories.
Whatever you pick, spend a little time on the 50 ohm output behaviour before your first real measurement, and keep the amplitude low until you know what the circuit under test can survive. That one habit prevents more damaged circuits than any choice on this list.
Our full guide to the [soldering stations](https://droid4x.com/best-soldering-stations-for-electronics/) that pair well with any of these is worth a read before you fill the rest of the bench.
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