Introduction
In electrical circuits, resistance is the property of an electric conductor by which it 
opposes a flow of electricity and dissipates electrical energy away from the circuit. Using a data logger to measure the resistance, the aim of this experiment is to prove the formulae used for calculating series and parallel resistance, and introduce the concept of electron flow through the different paths of an electrical circuit
Equipment required
- DrDAQ data logger
- Various resistors of different values
- Small terminal block (optional)
Experiment setup
- Connect the DrDAQ data logger to a PC
- Attach the DrDAQ 'R' connector to terminal board side A-1
- Attach the DrDAQ 'G' connector to terminal board side A-4
Method
Measuring resistors
Connect the resistor to measure (RMEASURE) to B-1 and B-4 as shown in Figure 1.
Use the Meter function in PicoScope to measure the resistance, note this value, and then repeat using different value resistors.
Figure 1
Measuring resistors in series
- Connect the resistors to measure (R1 and R2) to B-1 and B-2, and B-3 and B-4 as shown in Figure 2.
- Connect a wire from A-2 to A-3 as shown in Figure 2.
- Once again use PicoScope to measure the resistance, note this value, and then repeat using different value resistors.
Figure 2
Measuring resistors in parallel
- Connect the resistors to measure (R1 and R2) to B-1 and B-4 as shown in Figure 3.
- Use PicoScope to measure the resistance, note this value, and then repeat using different value resistors.
Figure 3
Questions and discussion of the results
- Why is the resistance lower when the resistors are connected in parallel?
- Why is the resistance higher when the resistors are connected in series?
- What is a benefit of connecting “loads” (light bulbs, motors,etc) in series? / parallel?
Further study
Connect up more resistors in series and in parallel to see what the results will be.
Think of suitable applications for a device that is able to sense resistance values.
