how to multimeter circuit

8/10

Well-Known Member
I have a string of 3 730nm 5v leds, which I've hooked up in a circuit with an led driver AND a small programmable timer. Last grow the circuit worked fine for a couple of months until it stopped working. It turned out to be a fault with the middle led, and I assume the other two are fine.

Now, the question is how I can measure the circuit with a multimeter?

The bad led has been replaced and I'm about to use the exact same circuit for this next grow, but I'm having a hard time figuring out what the programmable timer does to the circuit and if something is gonna break again.
 
Assumptions: leds wired in series, driver ac plugged into timer which is plugged into wall outlet.
Ohm out circuit. Measure resistance across all leds and wire testing all connections. Measure across driver unplugged and off for any shorts. Measure across ac plug for shorts.
Check timer for current capacity. Verify current demand of driver especially inrush current of the driver.
After all that you will have your answer.peace
 
the timer is between the driver and leds, like this:

Ac -> driver -> timer -> leds

The driver powers the timer and leds.

But I'll check everything as you described, thanks. I'm a noob with the multimeter and don't want to fry anything.
 
Timer should be FIRST and cut off the AC - you don't put switch on the DC side, only dimmers...
 
fuck the timer, what does it do? Bypass if possible
It turns the lights on for 10 minutes after main lights turn off.

you don't put switch on the DC side
Is this because of the "voltage jump" or spark that happens when the circuit is connected between a live driver and the leds? It says the timer gives no spark, but I don't know if that is possible or not.
Does this mean that I'll have to keep the driver -> led circuit closed at all times? I don't like messing too much with the AC side of things.

Edit: Maybe I should get one of these and have the timer control it. http://www.ebay.com/itm/MEANWELL-LD...959330?hash=item5439cc8be2:g:esYAAOSwA4dWKLuM
http://www.ebay.com/itm/1piece-mean...024604?hash=item48924adb1c:g:bfkAAOxygPtSx8ZW
 
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