Help find a relay substitute - Page 1
Forum section: electronics / repair

author: Traceless
author_rank: Frequent Contributor
timestamp: September 07, 2025, 02:08:38 pm
content: Hi everyone,I need to find a substitute for the type of relay shown below which doesn't seem to be available any more. The application is switching sockets on a multi-outlet power strip. I found various options for instance on mouser with similar voltage and current ratings but there seem to be different contact types (SPST, SPST-NO, SPDT, SPDT-NO, SPDT-NO, NC, 4PDT-NO, NC) I assume SPDT = single pole double throw, NO = normally open, NC = normally closed. That leaves me scratching my head about the last two contact types "NO, NC" which are normally open and closed simultaneously?I'm also not sure how to match the coil resistance, coil current, the coil type (dual-coil latching, non-latching) or the footprint, because I don't have the detailed specs of the original part.

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: September 07, 2025, 02:26:36 pm
content: Hi Traceless,SPST-NO-5V non-latching is what you want.Best regards

author: Traceless
author_rank: Frequent Contributor
timestamp: September 07, 2025, 02:36:39 pm
content: Hi Roehrenonkel,thanks for the hint, I think theJW1AFSN-DC5V-Fmight be a candidate, what do you think?

author: ledtester
author_rank: Super Contributor
timestamp: September 07, 2025, 03:33:40 pm
content: Quote from: Traceless on September 07, 2025, 02:08:38 pmCan you provide links to the relays you found? The datasheets should answer your questions.Not all relays have both NO and NC contacts. Some only have the NO contact, some only the NC contact and some have both.Here is a list of "4PDT-NO,NC" relays from Mouser:https://www.mouser.com/c/electromechanical/relays-contactors-solenoids/?relay%20contact%20form=4%20Form%20C%20%284PDT-NO%2C%20NC%29A look at some of the datasheets show that they all seem to have both NO and NC contacts.There is also this note from Digikey about what "form A, B and C" mean:https://forum.digikey.com/t/understanding-form-a-form-b-form-c-contact-configuration/811

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: September 07, 2025, 03:40:11 pm
content: Hi,https://www.eevblog.com/forum/Smileys/default/icon_smile_thumbsup.gif

author: fzabkar
author_rank: Super Contributor
timestamp: September 07, 2025, 04:30:46 pm
content: https://www.aferelay.net/bpm1/46-106.html

author: Traceless
author_rank: Frequent Contributor
timestamp: September 07, 2025, 09:09:14 pm
content: Quote from: ledtester on September 07, 2025, 03:33:40 pmthanks for linking the Digikey note about the relay form factors. The substitute candidate I found is already linked in my last post above yours. The main problem was less accessing the datasheets of the relays for sale rather than the lack of specs for the no longer available original. Thanks to the link provided by fzakbar, that problem is now partially solved.

author: Kwakerman
author_rank: Regular Contributor
timestamp: September 08, 2025, 07:37:18 am
content: Part number comes up on Amazon & eBayhttps://www.amazon.de/-/en/SSOPTMCB/dp/B0CX8X78LS?th=1https://www.amazon.com/HASMI-BPM1-SS-105LM-BPM1-SS-112LM-BPM1-SS-124LM-Electromagnetic/dp/B0CJ6GCW98?th=1https://www.ebay.com/itm/116358548240https://www.te.com/en/product-1461492-2.html

author: Traceless
author_rank: Frequent Contributor
timestamp: September 09, 2025, 09:02:14 pm
content: @Kwakerman: I saw the amazon and ebay ones when I was looking around on the web. The image I linked above is actually the amazon one. The problem with the amazon seller is that they wantbetween 28 and 60 bucks per relay. The ebay seller does sell salvaged ones. Since relays have a very finite life span and actually mechanically wear down in contrast to many ICs which will still be fine even if salvaged I didn't consider any of these. Especially when I can get new quality relays from reputable suppliers. But the TE link looks like an option, thank you.