Electricity Labs

1. Setting up the breadboard

2. Simple LED Circuit

1. What is the purpose of the resistor?
• To limit the current in the circuit (so that the LED doesn't blow)
2. Using Ohm's Law (V=IR), what is the current running through this circuit?
• 5V = I * 560 ohms
• I = 8.93 mA
3. Using Ohm's Law again, calculate the resistor value you would have to use in order to have only 15mA of current in this circuit?
• 5V / 15mA = ohms
• = 333.3 ohms
4. Assuming the LED drops 2.2V of voltage, how much voltage is dropped by the resistor?
• 5V - 2.2V
• = 2.8V

3. Simple LED Circuit With Switch

1. Looking at the schematic diagram, if you moved the switch so that it was connected between the resistor and the LED, how would the circuit's behavior change?
• The behavior does not change the switch still effects the circuit in the same way.
2. Looking at the schematic diagram, if you moved the switch so that it was connected between the LED and ground, , how would the circuit's behavior change?

• The behavior of the circuit would not change. No matter where the switch is it either allows current to flow through the circuit or not. 

4. Simple LED circuit with potentiometer

1. Why is the 560Ω resistor necessary?
• Because without it, when the potentiometer was turned to least resistance there would be too much current for the LED and it would blow.
2. How much current is flowing through the circuit when the 10kΩ potentiometer is turned all the way up (offering the maximum resistance)?
• 5V = I * 10560 ohm
• 5V / 10560 ohm = .47 mA
3. What other types of variable resistors do you know about (name at least 4)?
• photoresistor, thermistor, carbon film resistors, wire-wound resistor

5. Dueling LEDs circuit with potentiometer

1. Give a quick (1-2 sentences) explanation of why this circuit behaves the way it does. Include an explanation for how the current going through each LED is affected by a single turn of the potentiometer.
• When the potentiometer is turned it increases the resistance to one LED while decreasing the resistance to the other. As the potentiometer is turned back current more current is allowed to flow through one LED or the other causing it to light.

6. Capacitor charging circuit

1. How does adding a 2.2kΩ resistor between the pushbutton and the capacitor affect the capacitor's charging behavior?
• It will charge more slowly because it receives less current

7. Capacitor discharging circuit with LED decay

1. Looking at the circuit schematic diagam, why does the capacitor discharge up through the LED part of the circuit, and not directly from the capacitor down to ground?
• When the capacitor is fully charged it acts like a very high resistor, allowing no current to pass through it directly into ground, instead it discharges through the LED.