Category: Oscillators

Lou Garner Oscillator

Posted by on March 8, 2011


This is a modern take on the original Garner oscillator, unlike other versions this one won’t lock up in full conduction and is guaranteed to always oscillate using modern parts, whereas the original -after a few modifications- would only seem to work with germanium transistors.


The modifications are clear, we basically introduced a series resistor to limit inrush current during the low period, the low impedance side formed by the 10 Ohm resistor in Q2’s path was also adjusted, originally a higher resistance was found. We therefore achieved a safe balance which allows us to revive one of Garner’s proudest moments (Hey why else would anyone patent it otherwise, right?)

Another take:

Taking this oscillator as a baseline we can introduce other forms such as a sawtooth oscillator (It’s not perfect though!) with the help of our friend, capacitance.

How to:

To visualize the output waveform you could use a soundcard or a proper oscilloscope. Since the oscillating frequencies on both circuits are within the audible range you could also use a piezo speaker to hear it.

Fun isn’t it?, feel free to experiment and let me know if you find anything intersesting!.


Simple Oscillator MK2

Posted by on September 13, 2010

Not long ago I posted a schematic for what I believe to be one of the simplest oscillators one can build with just a few components. Even though it works perfectly, there’s always place for improvement!

This new version employs a “piezoelectric diaphragm” (or just piezo-speaker for short) and a couple more components to enhance the output power. So not only are we reducing the size and weight of the unit but we’re also increasing it’s sound output, neat!

The oscillator is still based on a Sziklai pair with feedback, so no surprises there.

Here’s the new schematic:

You can also download the PDF: very_simple_audio_oscillator_revised.

I suggest you breadboard this, it’s rather fun to play with the capacitor values, etc. I’m still looking to enhance it even further by lowering the power consumption, but I’m not sure if this is feasible given the nature of the oscillator…

One thing is for certain, this little circuit is a great buzzer for your power supply or almost any project that requires a form of audible signal. It’s got a wide operating range of input voltages, it’s fairly loud, cheap and simple… just the kind of circuit I like to build 🙂

I’d be delighted to hear about any modifications and/or alternative designs — So feel free to share!



Very Simple Oscillator

Posted by on April 17, 2010

This is the first oscillator I ever built. I remember looking at books and magazines, schematics on the net, etc. They were all either colpitt or hartley oscillators. Generally speaking while they’re simple enough, they require the use of proper inductors which is something that usually you don’t have when you’re just starting out or you can’t measure them because you don’t yet own the proper equipment (unless you’re lucky).

As to avoid frustration, you should ignore them for now and take a look at simpler oscillators like the one that follows: