Relay Coil Diode Specs

Status
Not open for further replies.
K

Ken1

Member
I have a circuit board with a Panasonic JW1FSN-DC12V relay on it. This relay makes use of an external surface mount diode across the coil. This diode is shorted. It has no markings on it. It is orange in color with a black band to indicate the cathode. Can someone suggest what kind of diode I can use to replace it and see if the board will work?
 
Sort by date Sort by votes
The relay coil is for 44mA and 12V. The diode will not see more than that.
As for diode voltage, look for 50V to 100V.
As for diode current, look for 50mA to 1A.
You can try to identify the size of the case of the diode.
digikey This link will take to Digikey.com with some search numbers set up for you. I entered diode, SMT, 50 to 100V, 100mA to 1A, standard, in stock.
I don't know what the part looks like. Here is an example of what might work. 1N4148WX-TP
 
Upvote 0 Downvote
The data says the coil current should be about 44mA, so any diode with a current rating higher than that, and a voltage rating higher than the coil voltage should work. But that's with no margin. personally, I'd choose a minimum 100mA at 50 Volts. But it's OK to use a diode with higher ratings.

https://na.industrial.panasonic.com...echanical-power-relays/series/1974/model/2186

But you'll also want to match the footprint of the existing part.

I don't think that I've ever seen a surface mount diode in an orange case.
 
Upvote 0 Downvote
The case is actually clear cylindrical "glass" I assume and the semiconductor material inside is the same orange color as many zener diodes.
 
Upvote 0 Downvote
Have you removed the diode and tested it?, it would be extremely unusual for such a diode to go S/C (I've never seen one do so) - but in the event it has?, it's pretty non-critical, a simple 1N4148 small diode is all that's needed for a small relay.
 
Upvote 0 Downvote
The relay did not want to work and in circuit tests revealed less than 1 ohm for the coil, so I removed the relay assuming it's bad and re-tested it and got 265 ohms. A resistance test of the coil's solder pads still showed the short. Removing one end of the diode showed that it is shorted and the rest of the circuit has a high resistance reading.
 
Upvote 0 Downvote

I'm curious as to the diode part number(?).
 
Upvote 0 Downvote
I replaced the diode with a 1N4148 and the relay works now. Don't know why the diode failed. It does resemble the one in the Digikey link. Thanks everyone!
 
Upvote 0 Downvote
Status
Not open for further replies.

Similar threads

C
  • Question
a question I don't understand about the diode
Replies
7
Views
4K
Diver300
D
B
  • Question
Solid State Relay for Hot Tub load Shedding?
Replies
4
Views
713
Battman
B
N
  • Question
Significance of resistance of the wireless power transmitter coil at resonance frequency
Replies
2
Views
721
danadak
C
  • Question
Is this sample question a zener diode - wave shaper question?
Replies
15
Views
3K
Tony Stewart
F
  • Question
Can someone help me with the function of this Diode?
Replies
16
Views
2K
MrAl
M
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…