: What does a resistor do to the current in a circuit?
In: Physics
It resists it.
Resistors resist electrical current flow. The main result is heat as the energy you are pushing into the circuit to move electrons hits the resistive element.
In a series circuit it will reduce current flow overall, the current at any point in the circuit is the same, it doesn’t cause a drop accross the resistor. But the increased resistance vs the voltage lowers the total current. Reduce the resistance with the same voltage and the current increases. Increase the resistance and the current drops.
It reduces current and causes a voltage drop. It converts power (current times voltage drop) into heat.
This has many different uses. A current-limiting resistor can reduce the maximum current something can draw. Two resistors in series can form a voltage divider. A shunt resistor can convert current into voltage for measuring purposes. A resistor can limit the rate at which a capacitor charges or discharges, creating an RC filter. Or it can be used to gently precharge large capacitor’s that would otherwise draw tons of current when empty. Many materials charge their resistance due to external factors such as light, temperature or voltage, making them useful as detectors or protection devices.
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