This circuit with zener diodes was found in documentation from the 90s. The zener diodes determine the lighting point of the LEDs. The circuit is for 12 V automotive batteries.
This is the simulation of a Ultrasound Receiver using the 741 IC, an operational amplifier....
The resonant circuit depends on the crystal frequency that can go up to a few megahertz. The...
With this circuit it is possible to select the upper or lower side band on an SSB transmission by...