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Code or name of LDR with special design


New Member
Hello everyone, I'm new to these forums and hope to get some help. During the maintenance to a broken equipment, I could find that the error was a ldr of special design (not sensitive enough to respond to the stimulus of a laser). I have searched all the electronic stores that I know but they had never seen the model. I would appreciate if any of you gave me the name of this ldr or the code to buy a spare part from abroad. Thanks.



Active Member
From the photos that appears to be more like some type of large-element photodiode or tiny photovoltaic cell, not an LDR.
It's certainly not like any I have ever seen, with an even dark blue or near-black element area.

Normal LDRs typically have a very obvious "interleaved finger" appearance.
eg. https://leetechbd.com/wp-content/uploads/2018/01/LDR-10-mm-Photo-Resistor.jpg

If that actually is one, it may have some kind of optical filter layer over it to limit it's response?

This looks more like yours; note the element appearance:

Edit - just noticed it has "+" next to one terminal; LDRs are not polarised, so it is not one of those.
Last edited:

Nigel Goodwin

Super Moderator
Most Helpful Member
$2.99 each seller is in Georgia FREE postage. For only $3 give it a try.

You can buy 30 of these from China $1.23 total with free postage but you have to wait a month for them to arrive. I bought 1 i only needed 1 and did not want to wait a month.

Perhaps you should try reading the previous posts?, or even looking at the picture the OP posted?, it's NOT an LDR so not much point buying any.


Active Member
It is not a LDR, it is a photocell/photodiode as in the excelitas link at post #2.
Similar :
----> https://www.aliexpress.com/item/10PCS-lot-photodiode-BPW34/32884835194.html?spm=2114.search0104.3.2.13b117adEKQ06F&ws_ab_test=searchweb0_0,searchweb201602_3_10065_10130_10068_10890_10547_319_10546_317_10548_10545_10696_453_10084_454_10083_10618_10307_537_536_10902_10059_10884_10887_321_322_10103,searchweb201603_57,ppcSwitch_0&algo_expid=f430a3c8-def2-4b1c-8756-c0268d7dad66-0&algo_pvid=f430a3c8-def2-4b1c-8756-c0268d7dad66

And can be tested with a voltmeter to its leads, covered and uncovered or shining light on it. It may be good with something else failed. In other words, it is a miniature solar cell.

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