4),
across 12V battery. 5. 5.3) have:
I I
T 3
∴
V
R
V
R
V
R
V
R
T
Now, since common all terms the equation, can divide both
sides leaving with expression for the circuit resistance:
1 1
T 3
R
Note that the derivation this formula given for information only.4) into equation (5.
.4
Resistors parallel.Basic scientific concepts electrotechnology
105
We are looking for expression for the equivalent resistance any paral-
lel circuit and, substitute equations (5. Craft
students need only state the expression 1/RT 1/R1 1/R2 1/R3 for par-
allel connections.3), and (b) parallel (see Fig.
Key Fact
Resistors
In parallel circuit, total resistance can
be found from
1 1
T 3
R
Example 1
Three resistors are connected (a) series (see Fig.3
Resistors series. For each method connection, find the total resistance and the values
of all currents and voltages.
R1 Ω
R2 Ω
R3 Ω
IT
I1
I2
I3
VT 12V
FIGURE 5.
R1 Ω
V1
R2 Ω
V2
VT 12V
V3
FIGURE 5
