This frequency divider by 10 uses discrete components only. Modern equivalent components can be used as the circuit is from an 80's documentation. Nearby frequencies can be used.
With this circuit it is possible to select the upper or lower side band on an SSB transmission by...
This is one of many zero crossing detector that can be found in this section. It was found in...
This circuit uses the 741 Operational Amplifier to drive two LEDs. The LEDs indicate the signal of...