Testing Kirchhoff’s rules by experiment

Materials required: two 1 ohm resistors, one 20 ohm resistor, one 2 ohm resistor, one 5 ohm resistor, three 3 volt batteries, connecting wires, two switches, a volt meter and an amp meter.

a) Set up the circuit as shown.

b) Close K1 and K2

c) Hook the volt meter in parallel and record the voltage for the following:a. a to h, a to b, a to f, f to e, e to d, d to c and c to b.b. record the values in a suitable table taking note of the current direction and if the voltage reading is

positive or negative.d) Open switch K1 and K2

e) Hook the amp meter in series from:a. a to gb. Close switch K1 and K2

c. Record the current values in a suitable table taking note if positive or negatived. Repeat a. to g. for a to i and a to j.

f) Open switch K1 and K2

g) Repeat b) to e) for a to d and a to e.h) Determine I1, I2 and I3 direction by measurement and label a suitable diagram. i) Determine the voltage drop or gain across every element in the circuit and label it on the diagram from j)j) Sum the potential change across the top loop and the bottom loop of the circuit.

1) Use Kirchhoff’s law and the values given on the question sheet to calculate I1, I2 and I3.2) Use Kirchhoff’s law and the given values on the question sheet to calculate the potential change in the top

and bottom loop.3) Compare the calculated flows from 1) and 2) to the measure flows, does Kirchhoff’s laws appear to hold

true? Why or why not.4) Measure the voltage of the batteries and use these values to calculate current and voltage as in in 1) and 2).

Do Kirchhoff’s laws appear to hold true now? Why or why not.5) Report the difference in current between measured in e) and calculated (in question 4) I1, I2 and I3 by

percentage.6) Report the potential difference between measured in j) and calculated (in question 4) potential difference in

each loop by percentage.

b a

g f e

c d

h20 Ω

5 Ω 1 Ω

2 Ω

1 Ω3 V

1.5 V

K1

K2

I1

I2

I3

i

j