Silly test light question.
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Silly test light question.
What is the difference between a high impedance and low impedance test light? My Haynes manual says to use a high impedance test light so that the computer doesn't get damaged. I checked Pep Boys and they had two kinds. One said not to use on computer circuits, and the other said computer safe. I guess the computer safe test light is a high impedance light? Can someone straighten me out?
Thanks.
Thanks.
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not positive on this but i belive that the difference in test lights is how much amprage the light will draw, if you are testing computer circuits it is almost always best to use a digital ohm meter over a test light 
and yes you would want to use the computer safe test light if that is what the hanes manual calls out for hope this helps
and yes you would want to use the computer safe test light if that is what the hanes manual calls out for hope this helps
Last edited by dmorgan; Dec 2, 2004 at 07:04 PM.
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high vs low
The difference is in how much current they need to light up. Also how much current, or voltage they will pass to the tested circuit. Impedence is, for DC circuits, the same as resistance. A light bulb test light is low impedence. A LED test light would be high impedence. Low impedence, the light bulb, lets lots of current through to fry electronic circuits. As noted a digital ohmmeter is always safe.
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Originally Posted by midlf
The difference is in how much current they need to light up. Also how much current, or voltage they will pass to the tested circuit. Impedence is, for DC circuits, the same as resistance. A light bulb test light is low impedence. A LED test light would be high impedence. Low impedence, the light bulb, lets lots of current through to fry electronic circuits. As noted a digital ohmmeter is always safe.
Thanks!
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