Posted By: Gusteve
Bench testing Voltage Limiter? - 07/29/10 08:21 PM
OK - I'm a little less ranty about this subject today than I was last night.
How do I bench test a voltage limiter? Seems like I'd:
Connect 12v+ to the 12v prong.
Connect a ground to the ground prong.
Connect my voltmeter to the 5V prong and also to the ground prong, and watch for 5V.
Do I need that little condensor thing connected? (And what's that for anyway? To stabilize the 5V pulse?)
FWIW - this is a new solid state limiter from redlinegauges. I just want to confirm it's good before I move on to the next step.
Posted By: Gusteve
Re: Bench testing Voltage Limiter? - 07/29/10 10:54 PM
I just spent some time searching, and I still don't see posts that talk about how to test one of these. Would my above posted process work?
Also - it appears that I don't need the capacitor thing at all, from what I recently read. Is that right?
Thanks in advance.
(How did people work on old cars before the internet?)
Posted By: Crunchy_Frog
Re: Bench testing Voltage Limiter? - 07/30/10 12:24 AM
I wouldn't test it without a load. I would try a 500 ohm 1/8 watt. But that's me.
Posted By: stumpy
Re: Bench testing Voltage Limiter? - 07/30/10 12:53 AM
Yes the meter is enough load.
Posted By: Crunchy_Frog
Re: Bench testing Voltage Limiter? - 07/30/10 12:59 PM
The meter will be a 10 megaohm load. I=E/R... That would be .5 microamps. Meters are not intended to be a load. Although, it probably wouldn't harm it. Some people will say it's fine. I'm not other people, and I would use a load. Ultimately, the choice is yours.
Posted By: Gusteve
Re: Bench testing Voltage Limiter? - 07/30/10 01:16 PM
How about if I just used a 12V lightbulb from the cluster? Or would that throw off my meter readings?
And by they way, thanks for bringing this up. Whether the meter is enough of a load or not is one thing, but if you hadn't mentioned this I probably would have applied the 12V first, and then proceeded to touch the meter to the 5V prong, so there would have been a period of time where there was no load at all.
Posted By: charger440sixpak
Re: Bench testing Voltage Limiter? - 07/30/10 01:57 PM
Meter by itself will work fine; I've tested a couple this way. Keep in mind that on the original units you won't see 5Vdc on the output. You'll see your meter go to 12Vdc (or whatever the input voltage is) and stay there until the internal coil heats up. After a a minute or so, the meter will start showing the output switching on and off to provide an approximate average of 5V. You can add the capacitor and see that it will slow down the movement of the needle on your meter (if the cap is working correctly) as the regulator switches on and off.
