Using a common crystal diode and a 741, this circuit can be used to detect microwaves. The circuit is from old documentation and the switch selects the gains.
An oscillator whose frequency can be adjusted between 500 Hz and 5 kHz with the use of a...
This circuit of industrial applications has an interesting characteristic: the relay is only...
Any TTL inverter can be used in this circuit. We found it in documentation from the 80s, but it...