Although the outputs on CIRCUITRON Detection Circuits are extremely flexible, they cannot directly control large amounts of current, or AC powered devices. With the addition of an external relay, though, these jobs are easily accomplished. It is possible to add a relay directly to the Detection Circuit output, but doing so requires that you wire a protection diode across the relay coil to protect the output transistor on the Detection board. Lower cost relays, such as the ones that Radio Shack sells are perfectly acceptable for this use, however, most of them are designed for printed circuit mounting, and you may find it difficult to make connections to them without mounting them on a circuit board. The CIRCUITRON ER-1 and ER-2 are circuits consisting of a relay, either single pole / double throw (SPDT) in the case of the ER-1, or double pole / double throw (DPDT) in the case of the ER-2, and all of the necessary driver circuitry to enable them to be easily and directly connected to the output of any CIRCUITRON Detection Circuit. The relay contacts can be used to control AC or DC circuits and are ideal for use with all CIRCUITRON Block Occupancy Detectors to provide automatic train control. The contacts on both of our External Relay Circuits are rated for a minimum switching capacity of 5 amps at either 12-24 volts DC or 110-115 volts AC. Contact life should exceed 50,000 operations. Both the ER-1 and the ER-2 have 12 volt relays and require a supply voltage of 11 to 15 volts DC. The ER-1 and ER-2 present a negligible load on the Detection Circuit to which they are connected as the control current is only around 2 milliamps.The ER-1 and ER2 are constructed on 1?? x 3? printed circuit boards.
