Activity 1.5B – Ohm’s Lawcontinued
Name:Date:
Class: Block:
Purpose
1.To study the mathematical relationship between voltage, resistance, and current found in all electronics circuits.
2.To construct electrical circuits and test for voltage, current and resistance using electronic test equipment
Equipment
Computer simulation software
5 volt power supply
ammeter
voltmeter
ohmmeter
Procedure
1.Complete the table below for the three variables of electricity:
Name / Symbol / Definition / Measured inVoltage
Current
Resistance
2.Label the Ohm’s Law formula wheel and determine the formulas below:
Convert all values to: AMPS VOLTS OHMS Do not use prefixes!!!
E = I = R =
Components you will use in this experiment:
You will be using a multimeter to test for circuit values. In order to get an accurate and safe reading, you must attach the meter into the circuit correctly. The correct method for each meter type is shown below:
Placement of an ohmmeter to measure resistance:
Placement of an ammeter to measure current:
Placement of a voltmeter to measure voltage:
Sample Problems:
1.If 15 volts are applied to a circuit having a resistance of 1 K ohms, how much current will flow?
Calculations
E = 15 Volts I = E / R
R = 1 K= 1000 ohmsI = 15v/1000
I = ?I = .015 Amperes
Circuit
Current flow in the circuit: .015 A (15 mA)
2.If a resistor of 2,700 ohms has a current of 2 milliamps flowing through it, what is the applied voltage?
Calculations
E = ?E = I R
R = 2700 ohms
I = 2 ma. = .002 AE = (.002A)( 2700 )
E = 5.4 volts
Circuit
The voltage applied to circuit is: 5.4 volts
3.A circuit has an applied voltage of 12 volts which causes 5 ma. of current to flow. What is the circuit’s resistance?
Calculations
R = E / I
E = 12 V
R = ? R = 12V / .005 A
I = 5 ma = .005 A R = 2400 ohms
Circuit
The resistance applied to circuit is: 2400 ohms
Now that you have confidence in OHM’S LAW, solve the following problems.
- Draw the CIRCUIT using computer simulation software.
- Show your MATH in the space provided.
- Label your answer.
- Tape a printout of the computer simulated circuit in the space provided.
1.A circuit has an applied voltage of 100 volts, and a resistance of 1,000 ohms. What is the current flowing in the circuit?
Calculations
E = ______
R = ______
I = ______
Circuit
Answer:______
2.A circuit which contains 100 ohms resistance has a current of 2 amperes. What is the applied voltage?
Calculations
E = ______
R = ______
I = ______
Circuit
Answer: ______
3.A circuit which contains 760 ohms resistance has a current flow of 20 ma. What is the applied emf?
Calculations
E = ______
R = ______
I = ______
Circuit
Answer: ______
4.A circuit has an applied voltage of 5 volts which causes 50 ma. of current to flow. What is the circuit’s resistance?
Calculations
E = ______
R = ______
I = ______
Circuit
Answer: ______
5.An applied voltage of 10 volts causes a current of 5 microamps to flow in the circuit. What is the total resistance in the circuit?
Calculations
E = ______
R = ______
I = ______
Circuit
Answer: ______
Breadboard the following problem and test for voltage, current and amperage using test equipment.
1.A circuit has an applied voltage of 5 volts which causes 30 ma. of current to flow. What is the circuit’s resistance? Use Ohm’s Law to find the correct resistance. Apply the 5 volts to the resistance on your breadboard and test for current.
Does the meter read 30ma?
Demonstrate the circuit to your teacher and get signature.______
2.A circuit has an applied voltage of 4 volts across a 360-ohm resistor. What is the circuit’s current flow?Use Ohm’s Law to find the correct current. Apply the 4 volts to the resistance on your breadboard and test for current.
Does the meter read the value you found using ohms law?
Demonstrate the circuit to your teacher and get signature.______
Questions
1.Your toaster has stopped functioning. How can you apply ohm’s law to help you find the problem in the toaster?
2.What are the circuit breakers in your house rated at? What do the breakers do?
Tom WhitePage 1 of 811/16/2018
Activity 1_5b--Ohms Law[1]