How to calculate total resistance of a parallel circuit
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How to calculate total resistance of a parallel circuit
Can anyone help me, please. I've got to find the total resistance of a parallel circuit. There are three given resistors (no given voltage, current, and power, it's only 3 resistors) and the third resistor is initiated into infinite. How can I solve the total resistance when there is an infinite given or value in one of the resistors? I read the Comparisons of Resistor in Series and in Parallels but this problem is not solved.
Re: How to calculate total resistance of a parallel circuit
Solve the parallel value of the two resistors that do not initiate in infinity.
When done, solve the resulting values of the new parallel with both values from infinity to whatever that third resistor is.
When done, solve the resulting values of the new parallel with both values from infinity to whatever that third resistor is.
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Re: How to calculate total resistance of a parallel circuit
It sort-of is in para 4-2 of your link. But anyway - In words
1 over R1 gives its' conductance
1 over R2 gives its' conductance
1 over R3 gives its' conductance
sum the conductances
1 over conductance total gives parallel resistance total
Can be any number of resistances. (1 or 0 would be silly though! )
Or, if all are equal then divide resistance of 1 resistor by the number of resistors.
an infinite resistance is an open, don't include in calculation.
(continued in next post.)
Cheers,
Code: Select all
1
Rt = --------------------------
1 1 1
---- + ---- + ----
R1 R2 R3
1 over R1 gives its' conductance
1 over R2 gives its' conductance
1 over R3 gives its' conductance
sum the conductances
1 over conductance total gives parallel resistance total
Can be any number of resistances. (1 or 0 would be silly though! )
Or, if all are equal then divide resistance of 1 resistor by the number of resistors.
an infinite resistance is an open, don't include in calculation.
(continued in next post.)
Cheers,
Dale Y
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- Posts: 1923
- Joined: Fri Aug 22, 2003 1:01 am
- Location: Izmir, Turkiye; from Rochester, NY
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Re: How to calculate total resistance of a parallel circuit
A shorter way to do the above for only 2 resistors is product over sum.
"|" used to mean parallel of the two names resistors
R1|R2 = (R1 * R2) / (R1 + R2)
To parallel R3 later
RT = (R1|R2 * R3) / (R1|R2 + R3)
called to diner, be back
okay, back
Since R for R1 parallel R2 was calculated first, then paralleling R3 with that previous is is two resistances again.
Cheers,
"|" used to mean parallel of the two names resistors
R1|R2 = (R1 * R2) / (R1 + R2)
To parallel R3 later
RT = (R1|R2 * R3) / (R1|R2 + R3)
called to diner, be back
okay, back
Since R for R1 parallel R2 was calculated first, then paralleling R3 with that previous is is two resistances again.
Cheers,
Dale Y
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