This variable frequency (VFO) oscillator was found in a Japanese publication of 1962. Coil details (in Japanese, but can be deduced) are next to the diagram covering the 3.5 MHz band.
This circuit triggers a relay when a pulse of light hits the LDR. The potentiometer serves as a...
In the figure we have the way to implement a NO OR or NOR gate with an operational amplifier. The...
The presented circuit is used to test ordinary fluorescent lamps. This circuit also has a mains...