Found in the May 1971 Radio Electronics magazine, this is the circuit for a commercial high-impedance instrument. The circuit uses 4 transistors and is powered by 2 9 V batteries.
This circuit is intended to apply the music signal from a stereo to a telephone line for the...
This tachometer from a 1994 publication has a bargraph scale with the well-known LM3914 integrated...
This traditional triplier configuration with the 555 can be found in other articles on the...