This unusual circuit from a Popular Electronics of the 90s uses LED indicators, operating as a bridge. The components used are common. It is based on the tuning of the signal by a PLL.
Found in a Popular Electronics from the 90s, this circuit can act as a transmitter for an audio...
With the circuit shown in the figure, the frequency of a 5 MHz oscillator controlled by crystal can...
This circuit with two HT2030s powers 6 LEDs in a decorative flashing system. The circuit is from...