| 摘要 |
<p>A temperature control circuit (20) includes a thermistor (14) which forms part of a bridge circuit (12). The state of balance of the bridge is detected by an integrated circuit (16) by comparing the voltages at T and REF. When the bridge is balanced or close to balance, the temperature is close to the desired temperature and the circuit (16) applies pulses of power to the heating element connected between the terminals (18). If the temperature drifts outside the permitted range centred on the desired temperature, the circuit stops supplying power or supplies power continuously. <IMAGE></p> |
