protecion for-against relay-coil

Fr: protection pour/contre les relais/bobines 1) top left - accelerated switching it's a bridge voltage divider with coil resistor, the capacitor temporary carry the power supply voltage directly to the coil, to speed up the contact closing >> speed up depends on how higher the power supply voltage is allow to temporary overvoltage the coil to speed up the contact closing 2) bottom left - delayed shutdown and power-up 3) bottom right - control latch note that the controlled power and the control circuit must use the same power supply, otherwise see my "power supply delay 3"... and the supplied circuit should being between the ground and the coil to avoid current disturb from pressed button. It also allow to lighten closing electric chocs on coil's contacts. 4) top right - PROTECTION for the command angainst the coil, and protection for closing of contacts against self-welding. These protections are critical for all the components based transistors. (+5V coil can generate -60V easily) Each protection (colored component) must be as close as possible from source of hazards.

published 10 years ago