Black Box Electronics Coursework

Diode:

You can notice that in the reversed direction there weren’t any current, but when it is normal it increases.

Filament Lamp:

It is not an ohmic because the graph isn’t straight and that doesn’t obey ohm’s law.

As more current flows, the metal filament gets hotter and the resistance increases. (Graph gets flatter).

I will do a test for each component once. For each test I will change the resistor 11 times, 5 times at normal resistor and 6 at reverse.

Equipment:

1. Voltmeter
2. Ammeter
3. Power Pack
4. Switch
5. Variable Resistor

For My Safety:

1. I mustn’t keep the power pack appliances running for a long time, because that will heat up the wires.
2. I mustn’t plug in too many plugs in a socket because using many plugs may cause a fire.
3. The stock must be far from any sink or water.

Prediction:

Now I will do a quick test, which will be:

Testing the components in a normal and switched connection. I will do this test to help me with my prediction.

These are my results for this test:

According to the results I got in my quick test I think that:

A is a ohmic conductor

B is a Diode

C is a Filament Lamp

Method:

1. Plug in the power pack.
2. Attach the wire from the positive (….) to the Ammeter.
3. Then attach the component to the ammeter.
4. From the component attach two wires to the voltmeter. 
5. From the other side of the component attach the switch.
6. Attach the switch to the variable resistor.
7. Finally attach the variable resistor to the negative (…..).

Results:

Component A

1. I used a Milliammeter to measure the current instead of the ammeter because it’s more accurate.
2. I used a voltmeter to measure the voltage.
3. I calculated the resistance using this rule:

Component B

Component C

Conclustion:

Evaluation:

In the first component I used an Ammeter and the second two experiments I used a Milliammeter because it is more accurate and the figures in components B and C are very small so I thought it would be more accurate if I used the Milliammeter.