Lab Practical

Question 1

Which two plugins do we connect to if we want to measure the voltage drop across a resistor?

Answer 1

Ground and Volts/Ohms

Question 2

Which two plugins do we connect to if we want to measure the current in a circuit?

Answer 2

Ground and 2A
-Current is measured in Amps

Question 3

Which two plugins do we connect to if we want to measure the resistance of a resistor?

Answer 3

Ground and Volts/Ohms
-Resistance is measured in Ohms

Question 4

If the green button is pressed, what are we measuring?

Answer 4

When the button is pressed in, we are measuring AC and if it is not, we are measuring DC

AC stands for alternating current
DC stands for direct current (constant)
Ex: DC V(t) = 5 V
AC V(t) = sin(wt)

Question 5

If the purple button is pressed, what are measuring? What do we call an instrument that measures this?

Answer 5

Purple button measures voltage and the instrument that measures this is called a voltmeter

Question 6

What is it were the pink button? Orange button?

Answer 6

Pink button measures Amps which measures the current and the instrument used to measure this is the Ammeter

Orange button measures Ohms which measures resistance is a Ohmmeter

Question 7

What does it mean if the DMM reads 0? What do we need to do to get a reading?

Answer 7

The setting is too low for the maximum range

Question 8

Sine Wave Equation

Answer 8

V(t) = Vo + Asin(wt - φ)

Question 9

Sine Wave Equation: what does each symbol stand for?

Answer 9

Vo: DC component (constant voltage)
A: Amplitude
w: Angular frequency (rad/s)
t: Time
φ: Phase shift

Question 10

Sine Wave Equation: how does angular frequency relate to frequency?

Answer 10

Only a 2π conversion needed to go from angular frequency to frequency
w = 2πf

Question 11

Sine Wave Equation: how does frequency relate to period?

Answer 11

f = 1/T

Question 12

Sine Wave Equation: how does amplitude relate to peak-to-peak?

Answer 12

Peak to peak is the very top to the very bottom whereas the amplitude is the midway point from the top or from the bottom

Amplitude being half of the peak to peak

Question 13

Sine Wave Equation: what is the max and min value he phase shift can take on in terms of degrees? In terms of radians?

Answer 13

The min value is zero and the max value is 360 for degrees

The max for radians is 2π and 0 for min

Phase shift shifts the wave from side to side

Question 14

Reading the Oscilloscope

Answer 14

When there is 0 input, there will only be a flat line on the screen reading
Y axis: Voltage (amplitude wanted in V)
X axis: Time (period)

Measuring Amplitude: multiply peak to peak bay the volts/div then divide the answer by half and change the units to V

Measuring period/frequency: (peak to peak or trough to trough) count the boxes to determine the number of divisions and multiply by time/div
-Units of frequency needs to be measure d in seconds to result in Hz

DC offset: below zero is negative and above zero is positive and zero means that the wave is centered at the middle ground

Question 15

Square graph: rise time and fall time?

Answer 15

Rise time is the time it takes to go from the very minimum to the maximum

Fall time is the time it takes to go from the very maximum to the minimum

Question 16

Equation that relates current, voltage, and resistance (Ohm’s law)

Answer 16

V = IR

Question 17

Equation that relates power to current and voltage?

Answer 17

P = IV (power is measured in Watts)

Question 18

Equation that relates power to resistance and voltage?

Answer 18

P = I^2R = IV = V^2/R

Question 19

Equation for the equivalent resistance of two resistors in series or in parallel?

Answer 19

Series (one right after the other):
R total = R1 + R2
R total < R1
R total < R2

Parallel (current able to split):
R total = R1R2/(R1+R2)
= R1 (R2/R1+R2) is <1
= R2 (R1/R1+R2) is <1
R total < R1
R total < R2

Question 20

Circuits: Reading the DMM

Answer 20

Use V = I(R total)

Question 21

Why can’t we place an ammeter in parallel with a resistor to measure the current like we place an oscilloscope/voltmeter to measure the voltage drop?

Answer 21

When we use the DMM is an ammeter it has a very low internal resistance whereas using the voltmeter causes it to have a high internal resistance