This sequential circuit of LEDs was found in a Popular Electronics from the 90s. The circuit can be programmed and an adaptation consists of using optical couplers to drive power loads.
This circuit uses a loop antenna to receive and amplify signals from the 60 kHz long wave band....
The frequency of this oscillator depends on R and C (see math section for electronics). The...
This common operational configuration can be implemented with modern equivalent. Next to the...