| 摘要 |
<p>The circuit controls the operating time of a heating system functioning at a working level and rest level, and the ventilation level gradually between a minimum value and a maximum value, whilst processing the signals delivered by a sensor. the signals from the sensor are converted into variation of electrical resistance which are converted into voltage variations by means of two resistance bridge networks. each of these networks delivers respectively a first and a second voltage to a first and second comparator circuit. The first comparator circuit feeds a step circuit which delivers an output signal to a relay when its input single exceeds a first step. The output signal stops when the input signal is less than a second step lower than the first. The relay controls the work or rest level of the heating system. the second comparator circuit controls a rectangular pulse generator operating at a frequency which is twice that of the electrical supply. The pulses control a triac mounted in the motor supply circuit of a ventilator. the width of each pulse is a function of the output signal of the second comparator circuit.</p> |
