‘Penny’ circuit plays a tune – just for a laugh
2SC1815 NPN transistor, 100uF cap, 104 cap, 7 strand coil, 850K slider, white LED. 2 pennies with homebrewed salts and mortar are the power source, for the WORST rendition of Silent Night you’ll ever hear 🙂 An AM radio picks up the oscillations of the circuit and I move the slider (name and nature eh) to vary the pitch of the sound. See Lidmotor’s channel for the fantastic circuit, which runs from uA and sub volt power.