5 rules for a parallel circuit - louisville electrical jatc · a few rules for a parallel circuit...
TRANSCRIPT
A Few Rules for a Parallel Circuit
1. A Parallel Circuit has two or more Paths for current to flow through.
2. Voltage is the same across each component in the circuit.
3. The sum of the currents in each path is equal to the current at the source (IT).
4. If one of the paths is broken, current will continue to flow thru the other paths.
A Few More Rules…
5. There are three formulas for finding total resistance.
6. Total Resistance is always SMALLER than the SMALLEST Resistor (or equivelent Resistor).
7. Adding more resistors will cause the total resistance to DECREASE.
. • A Parallel Circuit has two or more Paths for current to flow through. These paths are called branches.
• Voltage is the same across each component in the circuit
24v
24 v 24 v
* The sum of the currents in each path is equal to the current at the source.
* What goes in SHALL to come out!
Resistance Formula #1R/N (R over N)
NRRt
( Resistor Value)
(Number of Resistors)
When all resistors have the Same Value
Resistance Formula #1
NRRt 15
230 tR
Resistance Formula #2 Product Over Sum
When two resistors have different values
21
21
RR
RRRt
Resistance Formula #2
21
21
RR
RRRt
727.233
90
330
3 x 30Rt
Resistance Formula #3Reciprocal Method
When more than two resistors have different values
321
111
1
RRR
Rt
Put your Calculator to Use
You have a button that looks like this
You have a button that looks like this
X
1
1X
Punch in the Numbers
321
111
1
RRR
Rt
5 OHMS 7 OHMS 2 OHMS
Formula: 5 1/X +
7 1/X +
2 1/X =
1/X
2
1
7
1
5
1
1
tR =
Punch in the Numbers
321
111
1
RRR
Rt
5 OHMS 7 OHMS 2 OHMS
Formula: 5 1/X +
7 1/X +
2 1/X =
1/X
2
1
7
1
5
1
1
tR =
Punch in the Numbers
321
111
1
RRR
Rt
5 OHMS 7 OHMS 2 OHMS
Formula: 5 1/X +
7 1/X +
2 1/X =
1/X
2
1
7
1
5
1
1
tR =
Punch in the Numbers
321
111
1
RRR
Rt
5 OHMS 7 OHMS 2 OHMS
Formula: 5 1/X +
7 1/X +
2 1/X =
1/X
2
1
7
1
5
1
1
tR =
Punch in the Numbers
321
111
1
RRR
Rt
5 OHMS 7 OHMS 2 OHMS
Formula: 5 1/X +
7 1/X +
2 1/X =
1/X
2
1
7
1
5
1
1
tR =
Punch in the Numbers
321
111
1
RRR
Rt
5 OHMS 7 OHMS 2 OHMS
Formula: 5 1/X +
7 1/X +
2 1/X =
1/X
2
1
7
1
5
1
1
tR =
Punch in the Numbers
321
111
1
RRR
Rt
5 OHMS 7 OHMS 2 OHMS
Formula: 5 1/X +
7 1/X +
2 1/X =
1/X
2
1
7
1
5
1
1
tR =
If one of the paths is broken,current will continue to
flow.