BS170....are they all the same?

Nathan Stock

New member
I just completed my heatermeter 4.3 build... however I'm short 1 bs170. The first one I tried to us I bent the middle leg the wrong way and then broke it when I tried to correct it.

So I went to mouser ordered another one ...but the legs are slightly different. It also say wa12 vs wa 11 above the bs170.

Is this functionally the same?

Orginal (minus leg I broke) - new ones20200908_001959.jpg
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Bryan Mayland

TVWBB Hall of Fame
If you ordered BS170s then you should have BS170s, which would have the same specs and pinout. Looking at the two in your photo, looks like the new ones are "kinked lead" TO92 package and the original are straight lead so that could be the difference in marking. Some manufacturers also put a date code on the label, but I don't think the BS170s I've seen have that. Probably just the lead shape, which will make it a bit more of a challenge to insert because the spacing is wider so you'll have to sort of bend the sides in... which is a direction where it is very easy to break them. And the cycle continues!


New member
If you support the leg with a pair of thin needle needle nose (so pressure is not applied to plastic) and the either a second set of pliers or a socket or thin tube to bend the lead you will be less likely to break.