PIR LED 12V light circuit recommendations wanted.

[Harald Kapp]

The transistor's terminals aren't labelled in the drawing in post #14, which represents the transistor as a rectangle with 3 leads.

I was referring to post #16 with a correct symbol.
This is the problem with the kind of "schematics" as shown in #14: using non-standard symbols makes understanding hard. Presumably the box shows the frontal view of the transistor, Acc. to the datasheet the pins are from left to right
C-B-E

which fits the logic of the diagram nicely.

this forum doesn't allow you to edit posts

It allows me -> done

The transistor I used is unmarked so I couldn't look up which lead is which.

Have a look at one of these multifunctional component testers. These come in handy for such purposes (they may not be a hallmark of precision, but way better than guessing).

the HC-SR501 has a 1K resistor in series with the output

O.K., this escaped my attention.

 

[Sidecar Bob]

The Edit button is there for the most recent post but disappears once someone replies to it.

I had to replace my venerable 100,000 ohm/volt analogue TVM last year and I thought it was pretty high tech that the new digital multimeter measures capacitance. Now I'm thinking about a multi component tester

 

[Sidecar Bob]

After debating for a couple of days I ordered an LCR-T4 tester. It arrived today and I'm disappointed. It looks like a really neat item but the display was damaged in transit. The seller is going to send a replacement but I'll have to wait a few weeks before I get to play with it

40 years ago devices like this were science fiction and the the idea of it being cheap enough for the average home experimenter to afford was a pipe dream.

 

[Bluejets]

Best get yourself a cheap component tester........worth their weight as they say.

I added a hack rechargable battery and charger to the back of mine.

https://www.ebay.com.au/itm/154100949483

 

[Sidecar Bob]

Um... I bought the one Harald linked in post #21 from an eBay seller but as I said it arrived damaged so I'll have to wait for a few more weeks for the replacement.