Adapter for switching from primary to standby device upon failure of primary device

An appliance adapter for maintaining in continuous, alternate operation primary and standby power consuming devices, comprising:

• input terminals for applying alternating voltages from an external A.C. power source;
• a full wave rectifier connected to said input terminals for rectifying said alternating voltage, said rectifier having a pair of output terminals;
• first circuit means connected to said output terminals of said rectifier for applying rectified voltage to a primary power consuming device to keep the same in continuous operation;
• second circuit means connected to said output terminals of said rectifier for applying rectified voltage to a standby power consuming device;
• and
• automatic switching means connected in circuit with said first and second circuit means,
• said automatic switching means comprising:
• a transistor having a collector connected to said standby power consuming device, and an emitter connected to one of said rectifier output terminals and a base connected to said primary consuming device whereby said transistor is biased to cutoff when said primary consuming device is in operation and is biased to conduct when said primary consuming device fails, or is removed from said adapter;
• a silcon controlled rectifier having an input connected to said standby power consuming device, and an output connected to said one of said rectifier inputs and a gate connected to said collector of said transistor;
• and
• signal means having one end connected to the other of said rectifier inputs, and another end connected to said standby consuming device, whereby failure of said primary consuming device or removal thereof from said appliance adapter will cause said transistor to conduct and thereby connect said standby consuming device to said rectifier output means and simultaneously turn on said silicon controlled rectifier whereby said signal means are energized to indicate said standby power consuming device is operating.