| 摘要 |
<p>The control and protection circuit, for a transistor switch, applies a current pulse to the base of the transistor switch (1) so that it turns on and a voltage is developed across the load (2). The voltage is fed back to the transistor (3) controlling the transistor switch so that as long as this voltage is above a given limit the transistor switch is held on even after the current pulse has finished. If the load is short circuited the voltage across the load drops and the transistor switch is automatically biased off. The pulses are produced by an RC circuit (7) and applied via a third transistor (6) to the base of the control transistor. A current limiter (12) is provided to protect the transistor switch during the presence of a pulse. The limiter blocks the third transistor (6) if the current flows through the series resistor (13) is too large.</p> |
