116999
Description
Flashcards by eibhlinjones200, updated more than 1 year ago
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Created by eibhlinjones200
almost 11 years ago
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| Question | Answer |
| Current | Current is the flow of electrical charge around a circuit - basically the flow of electrons. It's measured in amps, A. More charge passes around a circuit when a higher current flows. Current will only flow through a component if there is a voltage across that component (unless the component is a superconductor). |
| Voltage | Voltage is the driving force that pushes the current round - kind of like "electrical pressure". Voltage is measured in volts, V. |
| Resistance | Resistance is anything in the circuit which slows the flow down. Resistance is measured in ohms (omega sign). |
| There's a balance: | the voltage is trying to push the current round the circuit and the resistance is opposing it - the relative sizes of the voltage and resistance decide how big the current will be. |
| Voltage and resistance | If you increase the voltage - then more current will flow. if you increase the resistance - then less current will flow (or more voltage will be needed to keep the same current flowing). |
| It's just like the flow of water around a set of pipes | 1) the current is simply like the flow of water. 2) the voltage is like the force provided by a pump which pushes the stuff around. 3) resistance is any sort of constriction in the flow, which is what the pressure has to work against. 4)if you turn up the pump and provide more force (or "voltage"), the flow will increase. 5) if you put in more constrictions ("resistance"), the flow (current) will decrease. |
| If you break the circuit, the current stops flowing | Current only flows in a circuit as long as there's a complete loop for it to flow around. Wire fuses and circuit breakers (resettable fuses) are safety features that break a circuit if there's a fault. |
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