Using the LM3909 this circuit was found in the January 1992 issue of Radio Electronics magazine. Resistor R1 should be chosen according to the table given next to the diagram.
This 7400 TTL circuit has a memory, keeping the LED on when a pulse is detected. The circuit must be...
August 2017 - STMicroelectronics' new DSL05 transient suppressors for 12 and 24 V voltages and...
The frequency depends on C, which must have the indicated value ratio, and also on R, which can be...