Explanation

Where resistors are wired in series (one after another) it is relatively simple to find out what single resistor could be fitted to replace them.

This simulator has 4 sliders which allows you to alter the resistance of 3 resistors to values varying from 1 to 100Ω and voltage from between 0 to 240V.

Sliders can be dragged to approx positions and then fine tuned by using left and right arrows.

On changing these sliders the total resistance RT, the current flowing in the circuit and voltage drops across the 3 resistors adjust automatically. The effect of these changes can be hidden or displayed by ticking/unticking various checkboxes.

Tasks

The following steps should be carried out and notes of values requested recorded along with research and explanations as to why. These explanations should then be submitted as a neatly formatted email to Robert.Eyre@Hull-College.ac.uk

1. With the three checkboxes unchecked move the sliders to random positions to generate different questions.
2. For each calculate the equivalent resistance RT and check your answer by clicking the Show RT checkbox.
3. Then using this confirmed RT value calculate the current in the circuit. This current may be found using the Ohms Law triangle and the voltage and RT you have just calculated and checked.
4. Check your answer by clicking the Show Current checkbox.
5. Now calculate the voltage drops across each of the 3 resistors using the Ohms Law triangle, the current you've just calculated and each of the resistors values.

Level 2 stuff below (lev 1 feel free to try if you want)

1. To make this last step more easy to grasp try setting all 3 resistors to 80V and the Supply Voltage to 240V and clicking all 3 checkboxes.
2. What do you notice? Explain why this is the case.
3. Try altering the resistance sliders to another combination that maintains the same equivalent resistance.
4. What do you notice? Explain why this is the case.
5. Try altering the supply voltage to 100V and 2 resistors to 25Ω and the 3rd to 50Ω
6. What do you notice? Explain why this is the case.
7. Set the Supply Voltage back up to 240V and R1 and R3 set to 1Ω and R2 to 100Ω
8. Record the voltage drops across each resistor in a table of results starting where R2 is 100Ω
9. Adjusting only the R2 value in 5Ω steps continue recording these 3 values of voltage drop until R2 gets down to 5Ω which will be your last entry in the table.
10. Look at the table of results you have built up and think what the resistances R1, R2 and R3 and their respective voltage drops might represent. See if you can explain the link to something you have learnt in module 203.