LAB 2:
BASIC DC CIRCUIT ANALYSIS
Resistance
It is important to understand how adding components to a circuit will affect the circuit.
Resistances placed in series add
directly.
Resistances placed in parallel add “inversely.”
In other words:
R
T
= A + B + C
R
T
= (AB)/(A + B)
Voltage Division
The voltage drops across resistors in series are directly proportional to the resistances.
In other words:
V
A
= V (A) / (A + B + C) V
B
= V (B) / (A + B + C)
Current Division
When a current encounters a branch in the circuit, the division of current is inversely proportional to the individual branch
resistances.
In other words:
I
A
= I
T
(B) / (A + B)
I
B
= I
T
(A) / (A + B)
Thevenin’s Theorem
All circuits, when viewed from the point of a single component, can be simply represented by one voltage source and one
resistance.
Thevenin’s Voltage (V
th
) is the voltage difference between the two terminals of the removed component.
Thevenin’s Resistance (R
th
) is the resistance between the two terminals of the removed component with all voltage sources
shorted.
If the removed component is placed in series with V
th
and R
th
, the voltage drop across and current through the
component will be the same as in the original circuit.
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View Full DocumentPRELAB 2
1)
Draw on the diagram above the direction of current through all wires.
2)
What are R
t
and I
t
?
3)
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 Summer '10
 BLOOMQUIST
 Resistor, power supply, Electrical resistance, rth, Voltage drop

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