Week 2 day 1

Lecture

Suicide sausage experiment

what will happen if we connect sausage into potential difference of 120 V?

 Sausage is slowly cooked over time.
Now we connected LED across sausage parallel to the current and perpendicular to the current

LEDs that parallel to the current light up, while  LEDs that perpendicular to the current source doesn't light up. For LED that light up, the farther the distance between the leg, the brighter the LED lights up. After a certain amount of time, the LED turned off.  WE  then sketch the possible current versus time:

Dependent source circuit problem:

Resistor connected in series:

Voltage splitter problem #1,
what is the Potential difference between Resistor 2?

Voltage splitter problem  #2
Find the needed resistor to split potential difference of 12 V to 3.3 V

LED Problem, Find the value of resistor needed to light up the LED

Find the Equivalent Resistance needed for this circuit:

Dusk to Dawn Light Lab

Pre-lab problem:
Find potential difference between photocell given that resistance of photocell is 5K ohm when it's bright and 20K ohm when it's dark :

Measuring the Resistance of resistor:

 Measuring the resistance of photocell when it's bright:

 Measuring the resistance of photocell when it's dark :

Measured Resistance for Photocell and Resistor.

First trial :

It lights up directly and went dimmer when we cover the photocell

Sources of Error:

1. Led is set up backward
2.We assign negative current on Waveform power supply

Second Trial :

 Overall Layout of the Circuit Connected to Voltage Scope on Waveform.

Scope

 Voltage across Photocell (dark)

Voltage across Photocell (light)

Summary:
Equivalent Resistance of resistor in series is equal to the sum of Resistance of all resistor. Equivalent Resistance of Resistor in Parallel is equal to the inverse of  the inverse sum..  The Resistance of Photocell increases when the light intensity goes down, increasing the current flowing through it. Higher value of current increases the potential difference between photocell. High Potential difference between photocell results in anode light up brightly.