| 摘要 |
PURPOSE:To make it possible to hold a timer circuit without providing a timer signal holding circuit separately, by equipping an oscillator, counter and oscillation stopping circuit. CONSTITUTION:The timer circuit consists of variable frequency oscillating circuit 1, counter 2 that generates a timer signal by counting oscillation pulses of oscillator 1 applied to clock terminal C up to a numeral for time setting, inverter 3 that inverts and applies the output of oscillator 1 to counter 2, and oscillation stopping circuit 4 that stops the oscillation of oscillator 1 in response to the timer signal of counter 2. Circuit 4 consists of transistor TR4a connected in parallel to capacitor 1e of oscillator 1 and resistance 4b flowing a base current from timer signal output terminal OUT to TR4a, which turns on in response to the timer signal to form a short circuit across capacitor 1e, stopping the oscillation of oscillator 1. |
