DS

  Coil Energy Saver Circuit Diagram . Some relays will become warm if they remain energized for some time. The circuit shown here will actuate the relay as before but then reduce the ‘hold’ current through the relay coil current by about 50%, thus considerably reducing the amount of heat dissipation and wasted power. The circuit is only suitable for relays that remain on for long periods. The following equations will enable the circuit to be dimensioned for the relay on hand: R3 = 0.7 / I Charge time = 0.5 × R2 × C1   Coil Energy Saver Circuit Diagram Where I is the relay coil current. After the relay has been switched off, a short delay should be allowed for the relay current to return to maximum so the relay can be energized again at full power. To make the delay as short as possible, keep C1 as small as possible. In practice, a minimum delay of about 5 seconds should be allowed but this is open to experimentation. The action of C2 causes the full supply voltage to appe...

This circuit is designed to help minimise the  quiescent power consumption of PCs and  notebooks, using just our old friend the 555  timer and a relay as the main components. The  circuit itself dissipates around 0.5 W in operation (that is, when the connected PC is on);  when switched off (with the relay not energised) the total power draw is precisely zero. A prerequisite for the circuit is a PC or note book with a USB or PS/2 keyboard socket that  is powered only when the PC is on. The power saver can be used to switch PCs  or even whole multi-way extension leads. The unit can be built  into  an  ordinary  mains  adaptor (which must have an earth  pin!) as the photograph of the  author‘s prototype shows. The  PC is plugged in to the socket  at the output of the power saver  unit, and an extra connection  is made to the control input of  the unit from a PS/2 (keyboard or mouse) socket or USB port. Only  the 5 V supply line of the interface is used.      PC Power Saver Image When butt...

  Coil Energy Saver Circuit Diagram . Some relays will become warm if they remain energized for some time. The circuit shown here will actuate the relay as before but then reduce the ‘hold’ current through the relay coil current by about 50%, thus considerably reducing the amount of heat dissipation and wasted power. The circuit is only suitable for relays that remain on for long periods. The following equations will enable the circuit to be dimensioned for the relay on hand: R3 = 0.7 / I Charge time = 0.5 × R2 × C1   Coil Energy Saver Circuit Diagram Where I is the relay coil current. After the relay has been switched off, a short delay should be allowed for the relay current to return to maximum so the relay can be energized again at full power. To make the delay as short as possible, keep C1 as small as possible. In practice, a minimum delay of about 5 seconds should be allowed but this is open to experimentation. The action of C2 causes the full supply voltage to appe...