Found in Radio Electronics from the 90s, this circuit has several outputs with different pulse times. The circuit is CMOS and can be powered by voltages from 5 to 15 V.
We found this heart rate sensor circuit in a Popular Electronics from the 90s. The placement of...
This circuit, found in an old magazine of the year 1968, uses a Power germanium transistor. This...
This project came out in an article of mine (Newton C. Braga) in the Popular Electronics magazine of...