Found in American documentation from the 1990s, this circuit generates signals in the 350 to 500 MHz range. The output power is in the order of 100 mW at 50 ohms.
The circuit shown is suggested by National Semiconductor's Linear Applications Handbook. The base...
This circuit uses a pickup coil to take the signal from a telephone line without contacts. The circuit...
In this circuit, the transistors are NPN for general use and the phototransistors can be replaced by...