This circuit tunes MW radios to apply the signal to a good audio amplifier. The circuit is from an old documentation. Transistors are general purpose types.
The frequency of this circuit is approximately 1 Hz. Whenever the output is at low level, the LED...
This circuit can be used in a digital measuring or shield interface. The circuit is from old...
In the figure we show how to implement a TTL photo-trigger with the 7413. This circuit can be used...