Experiment No.5 Capacitor

1. What is a capacitor?
An electrical component which can stores and release electrical charge. It consists of 2 metal plates and an insulating layer in the middle. The 2 metal plates are spaces for charges from the battery to accumulate. When a capacitor is connected to a power supply or a battery, electrons start to flow into the negative plates and charging up the capacitor. And when disconnected with the power source, the charges releases as there is nothing to hold the positive charges and the negative charges together, hence they tend to find an alternate way to get together. Note that the plates attract the charges from the battery as if accumulating on it is the closest the positive charges and the negative charges can get together. The truth is, the metals plates are nothing but 2D conductor which is area that stores charge instead of a wire. It is the insulator that attracts the charges, by having opposite charges facing the metal plate, though insulated, which will attract the opposite charges from the battery to near it.

2. Types:
Non-electrolytic capacitor : Regardless of polarity
Variable capacitor: Adjustable
Electrolytic capacitor: Large capacitance. Polarity correct. High leakage. Big. Dangerous.
Tantalum capacitor: Large capacitance. Polarity correct. Small & Expensive.

3. Identifying Capacitor size:
   Unit: Farad. 1 Farad equals 1 Amp-second at 1 Volt.
 Follow the EIA code and look it up with the capacitance table to determine the potential capacitance.

4. RC Time Delay or "Charging time".
Use the formula: T= R x C x 5.
Time constant: Why 5 is in the equation? Because whatever the total charging time, the time it takes to charge a capacitor up to 2/3 of its potential capacitance is 1/5 the total charging time.
Capacitance is in Farad. Farad is in the favor of the amount of charges(Coulomb) and Voltage, hence Amperage. Because it takes up Voltage to push the flow, Resistance will definitely affects Amps( Coulomp/sec) hence affects time.
Capacitance obviously affect charging time since more space means more charge can be stored, more time to reach full capacity.

5. Practice circuit:

The task revolving the charging time of the capacitor, this is the circuit where we can test with different variation, to see the relationship between reality and theory.
As we can see the opened switch is nothing of a circuit so when the capacitor is hooked up with the resistor and 12V it will start charging up.
When the switch is closed, remember that flow of charges always finds the easiest, fastest way to get together oppositely. So we can prevent the charging by closing the switch( bridge) for the sake of convenience in our timing experiment.
With different sizes of resistors and capacitors, we need to calculate their charging time first then compare them with the actual result. Checking charging time like this is a good way to determine whether the capacitor is working properly or not.

The 

The charging graph resemblances a type of exponential graph.