I.C. Oscillator/Component Tester
This project uses the IC (integrated circuit) as an oscillator, and allows you to test for resistance and capacitance. Equal values of resistance or capacitance will produce the same pitch from the Speaker.
Hook up the circuit and try placing the Probes across all unused components. Do you see any correlation between resistance and frequency? Between capacitance and frequency?
Try testing the CdS Cell while changing the light level on the Cell. There are many possibilities with this circuit.
By connecting the Probes between a metal chair and table, you may play tunes as you move your hands over the table or move your body back and forth. This would make a fun party game!
The basic IC hook-up used is described elsewhere (projects Capacitor as a Spark Suppressor in Capacitor Section and Light Controlled Burglar Alarm in Oscillator Section), so we won't repeat it here.
Here whit BA306 replacement schematic