Apparatus for connecting power sources with plug-in unit

摘要

An apparatus for connecting power sources to a plug-in unit has a plug-in connector and a plurality of connection control circuits. Terminal pins of the plug-in connector are connected simultaneously to a negative power source, a GND and a positive power source. When the negative power source and the GND are connected, a first connection control circuit is turned ON and connects the negative power source to a first load circuit. A second connection control circuit is turned on in response to an input from the negative power source supplied to the first load circuit, and supplies a GND signal to a third connection control circuit. The third connection control circuit is turned ON when the GND signal is supplied to the positive power source, and connects the positive power source to a second load circuit.