Technical data

44
arallel Circuits
etecting an Open in a Parallel Circuit
roject Objective:
• To provide experience with the change that occurs when an open develops in a parallel circuit.
• To verify that the total circuit current will decrease by the same amount that was passing
through the defective branch prior to it becoming open.
ems Needed:
- Electronics Trainer - Digital multi-meter
- Jumper Wires - Resistors: 47k, 100k, 220k
ake sure power supply is off when connecting meters or changing circuit components.
xperiment
P
D
P
It
M
E
1. Connect the circuit as shown in Figure 19-1.
2. Apply 30 volts to the circuit. Measure the total circuit
current and the individual branch currents. Calculate
R
T
.
I
T
= ____________________________.
R
T
= ___________________________.
I
1
= _____ _______________________.
______________
sistance is less than the ______________________ value resistance branch.
b.) lowest c.) both a & b
__________ of the branch currents.
branch. Keep the applied voltage at
ual branch currents. Calculate
R
T
.
I
2
= _________________________.
T
I
3
= _________________________.
R
T
will __________________. Therefore,
pe less _______________ path.
I = _________ _____.
2
I
3
= ____________________________.
The total re
a.) highest
The total circuit current is equal to the ____________
3. Remove resistor R
1
to simulate an open in that particular
30 volts and measure the total circuit current and the individ
I
T
= __________________________.
= _________________________. R
= __________________________. I
1
f any branch of a parallel circuit becomes open,I
ince the voltage remained the same, I
T
will __________________. s
Did the current through R
2
and R
3
change when R
1
became open? ___________________
R
T
increased because when R
1
became o n there was one _
The current through the open branch decreased to ________________ mA.
When R
1
became open, what happened to the current through the unopened branches?
Figure 19-1
+
_
47k
220k
100k
V
A
R
1
R
2
R
3
mA