| 摘要 |
PURPOSE:To obtain sure switching of a load circuit, by opplying a voltage drop of a resistor connected in series with the primary side of a transformer to cause a gate signal of a bidirectional power element connected in parallel with the primary winding of the transformer. CONSTITUTION:When a terminal of a secondary coil 3 is opened, since the impedance of the primary coil 2 shows a sufficiently greater value, a current flowing to the primary side is small. Thus, a gate signal to obtain a bidirectional power element 5 is not obtained from a resistor 4 and no current from a power supply E is supplied to a load L. When the terminal of the coil 3 is short-circuited, the impedance of the coil 2 is decreased and a current flowing to the coil 2 and the resistor 4 is increased. Thus, a voltage drop produced in the resistor 4 is increased, the element 5 is conductive and a current is supplied to the load L. Thus, at the turning-off of the element 5, no current flows to the load L due to the fluctuation of the current of the coil 2 and others and the system can be used for any capacity, either large or small, of load. |
