Daily Shop Improvement

[jcdammeyer]

I’m measuring 220-240 K ohms on one circuit, of six (now working) lights

That seems like a lot of ohms, but not a lot of amps?

Measuring the resistance of that sort of circuit won't predict current consumption. The problem at the moment of course is you don't have a stable 12V supply. If you could even 'borrow' the battery from a car to run a single light and measure the current with your meter then you'd have an idea of what you need to do.

LED lighting is pretty low power.
https://www.amazon.ca/Waterproof-Flexible-Daylight-Gardens-Kitchen/dp/B00HSF66JO
This are 18W at 12V. That means 18W/12V=1.5A

A search with these terms shows up all sorts of inexpensive AC adapters for 12V LED lighting.
https://www.amazon.ca/s?k=LED+lamp+...ed+lamp+power+supply,tools,141&ref=nb_sb_noss

And Amazon is really expensive for those sorts of things. If you can wait for Aliexpress to end of April.
Aliexpress power supply

Even Lee Valley Tools carries this sort of thing.

 

[Susquatch]

Measuring the resistance of that sort of circuit won't predict current consumption. The problem at the moment of course is you don't have a stable 12V supply. If you could even 'borrow' the battery from a car to run a single light and measure the current with your meter then you'd have an idea of what you need to do.

LED lighting is pretty low power.
https://www.amazon.ca/Waterproof-Flexible-Daylight-Gardens-Kitchen/dp/B00HSF66JO
This are 18W at 12V. That means 18W/12V=1.5A

A search with these terms shows up all sorts of inexpensive AC adapters for 12V LED lighting.
https://www.amazon.ca/s?k=LED+lamp+power+supply&i=tools&crid=1Y5K3FOF8S1MT&sprefix=led+lamp+power+supply,tools,141&ref=nb_sb_noss

And Amazon is really expensive for those sorts of things. If you can wait for Aliexpress to end of April.
Aliexpress power supply

Even Lee Valley Tools carries this sort of thing.

Or a trip through Chatham.

 

[Dabbler]

Why would one keep them in the first place

I regret getting rid of them now. I could have run them on a PiDP11/70 kit. it is available for $255 USD

No one mentioned FOCAL! I loved using APL - it was a great innovation that would eventually go nowhere. My first was an IBM 1130 running at 600KHZ, with between 4 and 16 cycles for each instruction, with 16 KB of memory, then programmed DEC PDP9's then 8's then 11's I used to own a working PDP8i, compete with 2 DECtape drives... those were the days!

 

[Chicken lights]

Measuring the resistance of that sort of circuit won't predict current consumption. The problem at the moment of course is you don't have a stable 12V supply. If you could even 'borrow' the battery from a car to run a single light and measure the current with your meter then you'd have an idea of what you need to do.

LED lighting is pretty low power.
https://www.amazon.ca/Waterproof-Flexible-Daylight-Gardens-Kitchen/dp/B00HSF66JO
This are 18W at 12V. That means 18W/12V=1.5A

A search with these terms shows up all sorts of inexpensive AC adapters for 12V LED lighting.
https://www.amazon.ca/s?k=LED+lamp+power+supply&i=tools&crid=1Y5K3FOF8S1MT&sprefix=led+lamp+power+supply,tools,141&ref=nb_sb_noss

And Amazon is really expensive for those sorts of things. If you can wait for Aliexpress to end of April.
Aliexpress power supply

Even Lee Valley Tools carries this sort of thing.

I tried amps and milli amps and got zilch. One single, new, light on a borrowed battery. Battery positive unhooked just jammed a 3/8” bolt in there to use as a terminal

I’m guessing it’s the dummy attempting to use the multimeter

 

[jcdammeyer]

I tried amps and milli amps and got zilch. One single, new, light on a borrowed battery. Battery positive unhooked just jammed a 3/8” bolt in there to use as a terminal

I’m guessing it’s the dummy attempting to use the multimeter

Should be at least about 20mA. Power from battery into meter positive lead, negative lead to the lamp. Other lamps lead to the negative post. From the picture it doesn't look like that.

Here's an example. The power supply is 12V and shows .41A. It powers the board in that little black box which sends messages out to the strip of LEDs to tell them to go to full intensity. The big clip leads are the power supply and red goes to the LED assembly. The black wire on the connector goes to a red clip lead which goes to the red probe on the meter. The black probe on the meter goes to the power supply negative black clip lead.

Meters normally have a fuse (sometimes very expensive). Make sure you have the meter set correctly and that you won't exceed the current setting.

 

[Susquatch]

As @jcdammeyer said, most meters have a fuse - sometimes two. Often the fuses only affect the current (amps) function. So your meter might work on volts but not current.

Or drop by the farm and we can figure it out together.......

Or maybe I'll be out your way in the near future.....

 

[jcdammeyer]

As @jcdammeyer said, most meters have a fuse - sometimes two. Often the fuses only affect the current (amps) function. So your meter might work on volts but not current.

Or drop by the farm and we can figure it out together.......

Or maybe I'll be out your way in the near future.....

From the first photo it almost looks like the probes were put across the power leads to the lamp. So current goes in one, out the other toasting the fuse in the process.

You will know the fuse has been popped by putting the meter in series with the power to the lamp under the 10A setting. If the lamp doesn't light, the fuse is popped. Hopefully it's a cheap one. My meter is a 600V one so the fuse was rated for that which made it a $30 item IIRC. So I 3D printed a small holder for a normal $1 fuse and that's what I use now. At least I think that's what I did. I'd have to pull the meter apart to find out.

 

[Susquatch]

From the first photo it almost looks like the probes were put across the power leads to the lamp

I think you meant to reply to @Chicken lights .

But ya, I had the same thought but figured you covered the details quite adequately on that.