The Tiny Tester is a ridiculously simple circuit that’s not immediately obvious as to why it’s useful. It’s not actually an effect designed to be used as a pedal, rather, it’s an oscillator that puts out a steady tone. Why would you want one? Because when you’re building a guitar effect, it’s very useful to be able to test your effect PCB before you box it up to be used. The Tiny Tester is designed to be used to give a steady signal to test your effects. Check out the Testing Rig, which also features a Tiny Tester circuit, if you want to see an application of this device.