We found this circuit in the Radio Electronics magazine of February 1993. The main integrated circuit is from that time and the power supply is made with voltages of 6 to 15 V.
With the configuration shown in the figure, a single pulse for a counter can be obtained from a...
With calibrated RV1 it is possible to find a zener diode voltage. The integrated circuit is 0 741...
This circuit was found on an 80's Ham Radio. The transistor admits equivalent. The circuit can...