This circuit was found in RCA documentation from the 1960s. The circuit uses components from that time and can measure speeds up to 10,000 rpm.
This circuit is like the previous one except that it can be triggered electronically. The circuit is...
Found in 90s Radio Electronics, this audio indicator makes use of an integrated circuit that is...
Found in the October 1992 Radio Electronics magazine, this oscillator is controlled by switch S1....