I was looking for a simple audio oscillator I could just grab and use with minimal cables. Plug in a RCA - Croc clips cable and switch it on.

I run the oscillator on a 9V battery and feed it through a little TDA7261 audio amp board that runs off 12V from AA batteries.

An RCA socket directly from the input to the amp and another from the amp's output. This gives me a High Impedance (5k+) output with low voltage and a Low Impedance (8 ohms) going up to several volts. Thus I can use it for a signal tracing or testing speakers and output transformers.

I use a multi switch, (2P6T) to change the capacitor value and a 2k potentiometer with a 1k resistor in series to change the frequency. The 1k resistor is to stop the pot from going to low in resistance - see the datasheet. A spreadsheet can be used to calculate the capacitor/resistance ratio to give the desired frequency ranges. You can use a 100k pot and a single cap, but it will provide an extreme frequency range.

Is it stable ? Its not perfect, but for a quick, cheap, simple, battery powered signal generator it works fine.