This bidirectional circuit was found in an American documentation from the 80's. The LEDs are common red, and the resistor is calculated according to the formulas next to the diagram.
This circuit can switch signals in the 3.5 to 30 MHz band. We found it in a QST magazine from the...
This is the receiver for the CB17133E. Its main feature is that it uses only transistors. The...
This is another one of the many versions of Nicad battery chargers that we have on the website and in...