Lab Report 1: Electrical Circuit Measurements

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Lab Report 1: Electrical Circuit Measurements
Aims and objectives
This laboratory exercise was carried out to achieve the following aims
1. To understand basic electrical circuits and apparatus such as the digital multimeter
2. To gain a practical understanding of Ohm’s law
3. To construct circuits on a bread board
4. To measure circuit parameters such as currents, resistance and voltages
5. To acquaint with laboratory procedures and standards
Apparatus used
1. Power supply
2. Bread board
3. Digital multimeter
4. Resistors
Procedure
The first part of this laboratory involves familiarization with the uses of the digital
multimeter. The use of the multimeter in the measurement of voltages, currents and resistance
was discussed ion details before commencing on the practical part. The value of the resistor
was then measured with the power supply to the circuit cut off.

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The second part involved the construction of a series circuit with three different resistances.
The individual resistances, voltages and current through the resistor network were then
measured and recorded. This was done to understand Kirchhoff’s voltage law.
For the third part of the exercise, a parallel network of resistances was constructed to
investigate Kirchhoff’s current law. A total of three resistors were used. The voltages across
the three resistors were measured as well as the currents flowing through the circuit branches.
Finally, a circuit of parallel and series resistor combinations was constructed and voltage and
current measurements carried out.
While taking measurements, the multimeter was connected across the resistor under
investigation while the multimeter was connected in series with the resistor for current
measurements.
Results and discussion
Multimeter:
To obtain the internal resistance of the multimeter, its two measuring probes were connected
together. The recorded resistance was 0.2 Ohms. It was observed that the multimeter gave
unexpected results whenever it was connected inappropriately. Besides, the fuse blew when
the multimeter was connected across a component during current measurement.
Bread board
The bread board is a temporary circuit board. Electrical components can be inserted to
construct an electric circuit and removed whenever necessary. All the circuits were made on
the bread board and connected to the power supply.
Experiment 1: Resistance measurement