a missconception about resistors

Started by gideon, February 04, 2005, 04:48:12 AM

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gideon

while debugging my easyface circut, i noticed that when i measure the resistors on the circuit with my analouge multimeter, some of them have a differnt ohmage when i switch the red/black probes.

is this a normal thing to get, my conception is that the resistance is across the resistor, and shouldnt be a plus-minus thing.

aside of that my easyface is all built up
(i had an old thread with lots of great people giving me tips )
http://www.diystompboxes.com/sboxforum/viewtopic.php?t=29123 , but i still get no fuzz. just a little clean boost.

i measure these voltages across:
when black probe is on the minus of the battery

red probe on Q2 : E - 4 / B - 5.2 / C - 5.5

                  Q1 : E - 3.8 / B - 4.8 / C - 5.2

These voltages above are when the trimpot is maxed.

Have a good weekend, Gideon

zachary vex

when measuring in-circuit resistances, there are multiple paths where current can flow.  sometimes those paths are polarized by the active components.  the proper way to measure component resistances in-circuit is to carefully lift one end by desoldering, or by assuming that the larger measurement (when switching the probes around) is closer to the correct value.  the lower measurement is probably due to current leaking through leads on the active components as they "turn on."

lightningfingers

Q1's emitter should be sitting at 0V so look for wiring mistakes around there.
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