This circuit was proposed by a 1965 Electronic Design. Its purpose is to widen the line transients to make them easier to see on common oscilloscopes.
We found this simple protection with zener diode in a 1967 Motorola documentation. The zener diode...
This circuit has been found in an old American documentation and is intended for calibration of radio...
Found in an American publication in 1967, this circuit generates pulses for the triggering of a LASER of...