Electronics > Beginners

setting the cutout on an old avo8 mk9

(1/4) > >>

m3vuv:
Hi all,i have an old avo8 that i need to refix the meter glass on,this means removing the movement,but this will screw up the overload cutout,grom memory this needs to trip at approx 12x whatever range its set on,so if i have a psu with 10v at 30 amp output am i right in thinking i need a 12 ohm resistor to limit the current to 12 amps?,just to set the trip up.tia

m3vuv:
am i correct in thinking a 12 ohm resistor will allow 12 amps of current to flow at 12v?,or am i having a brain fart?

MK14:
Incorrect.
https://ohmslawcalculator.com/ohms-law-calculator

m3vuv:
so after looking at that i need 1 ohm for 12a at 12v?,bear in mind this it a test to accelerate the meter needle for a split second ,the calcs say 144 watts power so i guess i can get away with my 30a psu set on 12v thru a 1 ohm 100 watt resistor with the meter on the 1 amp range should work?

MK14:
Yes, it should be ok for a very short period. But, to dissipate 100 watts, most modern resistors, need heatsinking via their metal tabs, otherwise they have much lower ratings, such as 25 watts (see datasheet).
Unless it is a huge type of resistor, such as a very old type, which usually didn't have metal tabs.

Navigation

[0] Message Index

[#] Next page

There was an error while thanking
Thanking...
Go to full version