This circuit is from a 60's documentation. The capacitance C1 can be between 20 pF and 0.01 uF depending on the generated frequency. Equivalent transistors may be employed.
The 4093 or any other NAND gate can be used for the very sensitive configuration of a R-S...
This circuit was obtained from Radio Electronics magazine of June 1964. The SCR may be a modern...
This circuit causes an LED to flash if the monitored voltage exceeds the value set in the pot. The...