Transfer Switches

An RF transfer switch (DPDT) is a type of armature relay that is composed of four ports (1–4) in one of two states (reset and set). In the reset state, port 1 is connected to port 2 and port 3 is connected to port 4. In the set state, port 1 is connected to port 3 and port 2 is connected port 4. The reset and set states of an RF transfer switch are illustrated in the following figures:

Transfer Switch Operation Cycle

The following figures illustrate the operation cycle of a transfer switch with 2-coil latching:

1. The transfer switch begins in the reset state.
   

   

2. Current flows through the lower coil to change the transfer switch to the set state.
   

   

3. The transfer switch is now in the set state.
   

   

4. Current flows through the upper coil to change the transfer switch to the reset state.
   

   

5. The transfer switch ends in the reset state.