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    Please could someone explain why there is a resistor in capacitor circuits when the capacitor in CHARGING?

    I've looked online but I don't really understand the answers I found.

    Thanks
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    (Original post by PhyM23)
    Please could someone explain why there is a resistor in capacitor circuits when the capacitor in CHARGING?

    I've looked online but I don't really understand the answers I found.

    Thanks
    Practically - to limit the current which otherwise would be high... reduce RF spikes which might interfere with other parts of the circuit.

    for exam questions - largely because the formulae don't give sensible answers when R=0
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    (Original post by Joinedup)
    Practically - to limit the current which otherwise would be high... reduce RF spikes which might interfere with other parts of the circuit.

    for exam questions - largely because the formulae don't give sensible answers when R=0
    Thanks for the response!

    Please may you explain what you mean by 'RF spikes', and how they interfere with other parts of the circuit?
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    (Original post by PhyM23)
    Thanks for the response!

    Please may you explain what you mean by 'RF spikes', and how they interfere with other parts of the circuit?
    when charging a capacitor through a very low resistance you get a high current flowing for a very short period of time, if you graphed current against time it'd have a very steep gradient - which means high frequency, high frequency electric current means radio transmitter.

    it'd interfere with nearby analogue radio receivers and might cause unexpected behavior in digital circuits.

    I don't think you'll get any questions on this at A level though
 
 
 
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