| 摘要 |
<p>The thyristor (2) control circuit using a phototransistor (11) at the input end, has a rectifier (7) in series with the anode of the thyristor. A limiting resistance (30) is in series with the rectifier, between the two a.c. connections (4,5) and the two d.c. connections (3,6). Across the two a.c. connections is a voltage divider formed by two resistances (14,15) and in parallel with them, two auxiliary thyristors (8,9). In series with the phototransistor is an auxiliary transistor (10) connected to the control input of the second (9) of the parallel pair. The cathode of this second thyristor is connected to the control input of the main thyristor (2). The junction of the two resistances forming the voltage divider is connected to the junction of two other resistances (12,13) forming another divider between the first a.c. connection (4) and the control input of the second of the parallel pair. A further resistance (17) is in parallel with the two other resistances (12,13). The connection between the two parallel pairs of resistances is formed by a diode (16).</p> |
