| 摘要 |
<p>PURPOSE:To speed up the rising of the temperature of a temperature controller, etc., by controlling the conduction angle of a semiconductor switching element to 100% for a specific time in the beginning of conduction. CONSTITUTION:When the coil of a relay 40 is energized and its normally open contact of a relay is closed, a signal from an AC power source after full-wave rectification is applied to the base of a transistor TR11, which turns off at the zero-crossing point of the AC power surce. At this time, a pulse signal appears at the collector of the TR11 and is applied to the base of a TR39, which turns on only for a short period at the zero-crossing point. Therefore, a short-period pulse signal is induced at a pulse transformer 41 at the zero-crossing point of the AC power source and applied as a gate signal to the gate of a triac 3. Therefore, the triac 3 turns on by 100% at the starting of the AC power source and a load 2 consumes 100% of electric power. This is held during the operation period of the relay 40. Therefore, heater temperature rises speedily.</p> |
