PIN diodes used as rf switch - Basic electronics circuits

This PIN diode rf switch is the ideal antenna switch for VHF and UHF and work with the PIN diodes which are special high frequency switching diodes with very low internal capacitance.

In this rf switch, the PIN diodes are used to shut on of off several antennas. The current source is a 12 volt circuit composed of a transformer, bridge rectifier and a regulator IC. In order to know which antenna is switched on, 4 LEDs are incorporated into the circuit.