I need to replace a suppression diode on a 12v relay.

Thread Starter

ilsinc

Joined Oct 17, 2021
5
This suppression diode has broken and when I inquired about it with the German manufacturer, they wanted me to replace the entire solenoid. (High initial cost + packaging + freight from Germany + etc.)
The spec sheet says the coil draws 10W @12v.
Can anybody give a replacement recommendation?
Does it matter which direction it is installed?
Thank You.
IMG_20211013_142533122.jpg
 

DickCappels

Joined Aug 21, 2008
7,981
Just about any 1 amp fast recovery diode should do the job well. If the solenoid is operated more than once a second I would go with a higher current rating (2 to 3 amps) for margin.
 

DickCappels

Joined Aug 21, 2008
7,981
Some examples of diodes that should work fine, in order of price (low to high) from a S.E. Asia distributor. In single unit quantity they are all less than 40¢ (U.S.) and most less than 20¢
Any of the UF400X (UF4001 through UF4007)
1N4937
FR157-TR
1N4937
1N496
RGP10M
FR207
1N4735
BYV26E
FR302-R0
FR303-R0
MUR160RLG
EGP10GE-E3/54
MUR120RLG
MR856RLG
FR303G-K R0G
FR302G-K R0G
MUR115G
MUR460RLG
FR602
SF54

If the switch that drives the solenoid is not a semiconductor (Not a Transistor, MOSFET, etc.) then you can safely go for a 1N4001, about a penny each.
 

crutschow

Joined Mar 14, 2008
28,201
You shouldn't need a fast recovery rectifier (it's the turn-on time that's important and there is not much difference between a standard diode and a fast-recovery diode for that parameter).
A 1N400x should work fine for a value of 1 to 7 for x.

The diode direction is not arbitrary.
It must be connected with its cathode to the positive voltage to the relay coil.
 
Last edited:

Thread Starter

ilsinc

Joined Oct 17, 2021
5
Some examples of diodes that should work fine, in order of price (low to high) from a S.E. Asia distributor. In single unit quantity they are all less than 40¢ (U.S.) and most less than 20¢
Any of the UF400X (UF4001 through UF4007)
1N4937
FR157-TR
1N4937
1N496
RGP10M
FR207
1N4735
BYV26E
FR302-R0
FR303-R0
MUR160RLG
EGP10GE-E3/54
MUR120RLG
MR856RLG
FR303G-K R0G
FR302G-K R0G
MUR115G
MUR460RLG
FR602
SF54

If the switch that drives the solenoid is not a semiconductor (Not a Transistor, MOSFET, etc.) then you can safely go for a 1N4001, about a penny each.
Thank you very much!
 

Thread Starter

ilsinc

Joined Oct 17, 2021
5
You shouldn't need a fast recovery rectifier (it's the turn-on time that's important and there is not much difference between a standard diode and a fast-recovery diode for that parameter).
A 1N400x should work fine for a value of 1 to 7 for x.

The diode direction is not arbitrary.
It must be connected with its cathode to the positive voltage to the relay coil.
I understand. Thanks for the info.
 

DickCappels

Joined Aug 21, 2008
7,981
If the diode see temperature extremes, then the "s" curve or a zigzag is a good idea to relieve stress in the lead. I wish I had thought of that!
 
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