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Topic: Project 04 - Why do we need the 10k resistor in series with the phototransistor? (Read 997 times) previous topic - next topic


Hey there,

i would like to know why it is needed to put a 10k resistor in series with the phototransistor.
As far as i could find out a transistor is something like an amplifier which can open the circuit with a very small current from the basis to let more current flow through the transistor emitter. So a small current flow from the base can amplify the current which flows from the power supply through the emitter with a gain factor proportional to the base current.
So far so good i think... but why the 10k resistor?

Thanks in advance :)


For questions like this, which aren't directly related to the starter kit, you'd probably be better off asking in the General Electronics section. But bear in mind that not many people have the starter kit and won't be familiar with Project 4, so add a drawing of the part of the circuit you are referring to.
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