Power supply circuit of a control contact and its application to the control of a delay of rest of a relay

摘要

With this circuit, a current may be caused to flow through a contact (K) controlling the voltage supply of an electronic control circuit (24), of sufficient intensity for the reliability of the contact to be good, without the current flowing in the control circuit (24) being too high and this independently of the supply voltage (terminals E, 44) applied to the supply terminals of the user circuit (U). For this, the control circuit (24) is fed with power when the contact (K) is closed, through said contact (K), a first diode (31) and a resistor (32) connected in series, whereas a piloting circuit (11), which is an integrated time delay or memory circuit associated with said user circuit (U), is then supplied through said contact (K) and a second diode (26). When contact (K) is open, said piloting circuit (11) is fed through a third diode (29) and a Zener diode (30), the second diode (26) then preventing the control circuit (24) from being supplied with power.