This filter that rejects a frequency range determined by the double-T was found in the August 1993 Electronics Now magazine. The source must be symmetrical.
Found in an Electronic Design from the 90's, this circuit uses common components. The circuit is...
When the sensor receives light, the relay closes its contacts and remains so even after the light...
This circuit produces pulses of 90 V at intervals that can reach 5 minutes. The circuit is from a...