Diodes on relays are to shunt the inductive kickback.
Sometimes the diode is on the relay, sometimes on the controlling PCB.
But when you kill the current to a relay coil that infinite voltage from the
collapsing field needs to go somewhere.
Without the diode it generally blows out the transistor controlling the
coil.
Is any of that helpful?
From: Carl Peterson
Sent: Monday, January 29, 2018 8:32 AM
To: [email protected]
Subject: [AFMUG] OT Resistor VS Diode in Relay
I've got a bad relay on a lift.
VF4-15H11-C05 which shows "Resistor 2.7 kΩ" as a special feature. I can't
source that relay anymore but can source "VF4-15H11-S05" which shows
"Bracket, diode (cathode at 86)" as special features.
I don't care about the bracket, in fact it would be neater if it were
mounted anyway. My question is wether there is anything that I should be
concerned with in using a relay with a diode instead of a resistor.
