MFOS 9V Battery Powered Mini Function Generator

From MFOS - A 9V battery powered mini function generator PCB!

This is for a PCB only, suitable for multiple formats.

Availability: In stock




This is a fairly simple project and can be built by someone just getting started in electronics. You will need electronic tools and soldering equipment and you must know how to build a case to house the project. The case can be as simple as a cardboard box or as elaborate as you want. Only the schematic, circuit description, pc layouts and a suggested panel layout are provided. Please read over the entire project before ordering PC boards or other products.



Often in synth-DIY trouble-shooting and/or circuit experimentation, a signal source with variable frequency and amplitude is just what you need to test a circuit’s behavior. If the signal source has a variety of wave-shapes, it will serve in more scenarios. This article will present a 9V battery-powered function generator that outputs sine, square, and triangle waveforms. The frequency is adjustable from about 20 Hertz to about 11KHz and the output level can be varied from 0 to about 3V, peak to peak. I kept the output level within this range as the circuit is essentially powered by a virtual +/-4.5V power supply and I wanted the unit to continue to function as long into the 9V battery’s depletion as possible. The circuit drains about 11mA when used with the LED shown in the schematic. However, if you buy a power switch with an obvious passive indication of state, you can leave the LED off and the circuit will draw about 9mA. In either case, you can count on a good long life on a 9V alkaline battery. The signal can be injected into the input of a VCF or VCA circuit under development or a mixer or an amplifier input you want to test. Since it’s battery powered you can leave one in your toolbox.

Capacitor C2 may have the value .002uF or .0022uF.


9V Battery Powered Function Generator Schematic

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Specs & Downloads

Specs & Downloads

Manufacturer MFOS
Depth No
+12V No
-12V No
+5V No
Additional Resources


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