This circuit causes an LED to flash at a frequency determined by the capacitor. The circuit is powered by only 3 V and can be used for signaling.
This power source was found in a 1968 Electronics World. The transistors are from that time. The...
We can use this circuit to connect low impedance microphones and even small speakers used as a...
This audio millivoltmeter was found in a 1992 publication. It can still be assembled, as the...