| 摘要 |
<p>PURPOSE:To prevent the output of a reference voltage generating circuit from varying against a noise with small pulse width by utilizing the response delay time of a relay for a circuit which uses the relay. CONSTITUTION:The input of the reference voltage generating circuit 7 is connected to an output terminal to which one terminal of the relay contact 2a of the relay 2, i.e. a lamp 5 as a load is connected. Then the circuit outputs the 1st reference voltage Vth1 when the output of the relay 2 is at a high level or the 2nd reference voltage Vth2 when at a low level. When a noise is applied, the potential at a point (a) varies from Vth1 to Vth2 momentarily and the voltage to the uninverted input terminal of a comparator 1 rises above the voltage at the inverted input terminal, so the voltage at a point (c) goes up to the high level, but the potential at a point (d) does not drop to the low level because of the response delay of the relay 2. The pulse width of the noise is shorter than the response time of the relay 2, so the output point (a) of the circuit 7 returns to Vth1 and the potential at the point (c) also reduced to low.</p> |
