Why is there no power loss when the switch is off?
Why is there no power loss when the switch is off?
When the switch is off, there is no current through it (although there is a voltage VSacross it). And therefore, there is no power dissipation. When the switch is on, it has a current (VS/ RL) through it, but there is no voltage drop across it, so again there is no power loss.
Can a switch be turned off during a power outage?
However, if we are out of the house, this is not possible. So, I was thinking of some sort of “automatic switch” which disconnects the device from its power source by opening the circuit when there is a power outage, and which requires human action to turn back ON again.
How long does it take for a switch to turn on?
A real switch takes a finite time tSW (ON) to turn on and a finite time tSW (OFF) to turn off. These times not only introduce power dissipation but also limit the highest switching frequency possible.
Why do I need a zero volt switch?
Most manual ‘contactors’ (industrial switches) have this ‘zero volt drop-out’ facility, mainly to stop machine tools suddenly restarting themselves when power is restored after an unexpected power cut. You wouldn’t need one per device, you can get ones big enough to use one per circuit, or one per house.
When the switch is off, there is no current through it (although there is a voltage VSacross it). And therefore, there is no power dissipation. When the switch is on, it has a current (VS/ RL) through it, but there is no voltage drop across it, so again there is no power loss.
When does the latching relay turn on and off?
There is also a latching relay that depends on Acc/On switched power, where it turns off once the car is turned off, and only turns on when you press the button when the car is on. But if you add a second relay, you get the pulsed on, and NO button setup you want.
A real switch takes a finite time tSW (ON) to turn on and a finite time tSW (OFF) to turn off. These times not only introduce power dissipation but also limit the highest switching frequency possible.
What happens when relay 2 loses 12V power?
Trigger the circuit, Relay 2’s Normally Closed contact allows Relay 1 to activate, latching it from the 12V power source through Relay 1’s Normally Open contact. Circuit will stay on until 12V power is lost, or until Relay 2 is activated by grounding the coil through the Normally Open Button.
