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# Resistor Voltage Drop

Is there any way to calculate the voltage drop of a resistor value? For example, if I had a 47 ohm resistor, would its voltage drop equal -30V, -857358V, or -0.5V?

2791Views5Replies

Is there any way to calculate the voltage drop of a resistor value? For example, if I had a 47 ohm resistor, would its voltage drop equal -30V, -857358V, or -0.5V?

## Discussions

A zener diode will cause a (more or less) fixed voltage drop regardless of current through it, up until the time that it is destroyed. (of course, resisstors are also subject to burning out under similar circucumstances...) (Note also that this is not the way that zener diodes are USUALLY used...)

Really? I did not know Zeners could do that.

depends on how many amps you are drawing

Unfortunately, I have no way of knowing how much current is being drawn.

Ohm's law explain the relationship of Volts, amps and resistance.

V=IR

The voltage across a resistance is directly related to the current passing through it.

A 47 ohm resistor could conceivably have each of those three voltage drops in three different circuits.