| 摘要 |
PURPOSE:To detach a main circuit at the primary side from a power source automatically by mounting a timer which changes the base potential of a transistor installed at the primary side of a transformer into inverse potential after a fixed time after turning a starting switch ON and a resetting circuit. CONSTITUTION:A switch 2, the primary side of a transformer 3 and a section between an emitter and a collector of a main transistor 4 are wired in series with a main power source 1, an output terminal of an oscillation circuit 5 is wired to a base terminal of the main transistor 4 and the main transistor 4 is conducted periodically, and an inverter supplying AC output to load 12 wired to the secondary side of the transformer 3 is constituted. The timer 11 consisting of a resistor 6, a capacitor 7, a transistor 8 and the like is mounted to a base of the main transistor 4 in the inverter, and base potential is changed into inverse potential after a fixed time (by a time constant of the resistor 6 and the capacitor 7) after turning a starting switch 2 ON. The secondary currents of the transformer 3 are detected by means of a transformer 13, and an initial condition of said timer 11 is reset by means of a transistor 16. |
