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# Physics - LDR Circuit Watch

1. I saw a diagram that showed a circuit with an LDR that turned a light on during the dark and it looked something like this:
___CELL___
|```````````````|
|___LDR___|
|```````````````|
|___BULB__|

It said during light conditions, the LDR has low resistance and current runs through it.

My question is, if something has a resistance of 0 (I know this isn't possible but for the sake of argument) will it take all of the current so the other components are left with no current?
2. No, all components would have a current flowing through as otherwise the circuit would not work. It is also dependent on which type of circuit it is in. In series ciruit, the current is the same on any component so it would not vary unless it is in a parallel circuit in which the current through each component adds up to the toal current. Hope this helped!
3. (Original post by one_man_abdullah)
No, all components would have a current flowing through as otherwise the circuit would not work. It is also dependent on which type of circuit it is in. In series ciruit, the current is the same on any component so it would not vary unless it is in a parallel circuit in which the current through each component adds up to the toal current. Hope this helped!
It was in parallel, as my diagram should have told you. If what you say is true then surely the bulb would be powered since it has a current running through it.
4. The current from the bulb (A2) + the current from the LDR (A1) would equal the current from the battery (A). A = A1 + A2. Your question, if there was 0 resistance, would it affect the other components - no as there's 0 resistance meaning very high and surging current which would flow through all the components.
5. (Original post by one_man_abdullah)
The current from the bulb (A2) + the current from the LDR (A1) would equal the current from the battery (A). A = A1 + A2. Your question, if there was 0 resistance, would it affect the other components - no as there's 0 resistance meaning very high and surging current which would flow through all the components.
I don't think I explained myself very well. I made a diagram in paint. What would the current be for each component?
6. The formula for this I think would be A = V ÷ R, so the first one would be 10 ÷ 0.00000001 = 1,000,000,000 A which might not be right or even possible but if so that is a lot of amps so the component and/or circuit would be fried/overheated. The second one is 10 ÷ 5 = 2 A. Hope this finally helped!
7. The young fellow is right, A= V÷R... Its parallel each component takes its own calculations... Of course if you wanted the entire current then you would proceed to add the currents of the individual components... So he was right
8. No solution in my opinion but thanks for trying. Perhaps I still hadn't explained myself correctly.

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Updated: April 2, 2016
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