Ohm’s Law Ohm’s Law Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Ohm’s Law

Ohm’s Law Georg Ohm Ohm’s Law Ohm’s Law Chart Ohm’s Law Practice Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Ohm’s Law Georg Ohm Ohm’s Law Ohm’s Law Chart Ohm’s Law Practice This presentation is intended to be used with Activity 6.2.4 Ohm’s Law.

Georg Ohm Georg Simon Ohm 1789-1854 German Physicist / School Teacher Ohm’s Law Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Georg Ohm Georg Simon Ohm 1789-1854 German Physicist / School Teacher Discovered the mathematical relationship between current, voltage, and resistance

V=IR I=V/R R=V/I Ohm’s Law Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Ohm’s Law If you know 2 of the 3 quantities, you can solve for the third. Quantities Abbreviations Units Label Voltage V or E Volts V Current I Amperes A Resistance R Ohms Ω V=IR I=V/R R=V/I

Cover the quantity that is unknown. Ohm’s Law Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Ohm’s Law Chart Cover the quantity that is unknown. V I R Solve for V V=IR

Cover the quantity that is unknown. Ohm’s Law Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Ohm’s Law Chart Cover the quantity that is unknown. V I R Solve for I I=V/R

Cover the quantity that is unknown. Ohm’s Law Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Ohm’s Law Chart Cover the quantity that is unknown. V I R Solve for R R=V/I

New Prefixes mA Milliamp = 0.001 amps KΩ Kilo ohm = 1000 ohms

When making circuit measurements, it is important to always work in Equivalent Units. The Equivalent Units are… KΩ V mA

For our lab, we will be using Ω V A For our lab, we will be using V, KΩ and mA.

Your Turn! V I R V mA KΩ V A Ω

Remember our Multimeter? Ohm’s Law Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Remember our Multimeter? Let’s look at how they are used to measure variables in Ohm’s Law.

Measuring Voltage Measure across a component. Switch Battery Resistor Using a Multimeter Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Measuring Voltage Measure across a component. Switch Battery The positive and negative signs represent polarity and flow. A digital multimeter will give a negative reading if the positive and negative terminals are reversed. The voltage reading can be different between any measured component. Resistor Light

Measuring Current Circuit flow must go through the meter. Switch Ohm’s Law Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Measuring Current Circuit flow must go through the meter. Switch Battery Resistor Light

Measuring Resistance Measure across the component being tested. Ohm’s Law Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Measuring Resistance Measure across the component being tested. Power must be off or removed from the circuit. Switch Battery Resistor Light

Now Back to Ohm’s Law Ohm’s Law Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Now Back to Ohm’s Law

Ohm’s Law Practice Calculating Resistance Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Ohm’s Law Practice Create a series circuit with a DC source and the two supplied fixed resistors with the color bands visible. Calculating Resistance Power the circuit and use a multimeter to measure the voltage drop across each fixed resistor. Add those values to get the total voltage. Record that value on your activity page, using volts for your units. Remove one of the connectors and measure the current with the power on. Record that value on your activity page, using mA (milliamps) for your unit.

Ohm’s Law Practice Calculating Resistance Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Ohm’s Law Practice Calculating Resistance Use Ohm’s Law to calculate the total resistance delivered by the fixed resistors. Record that value on your activity page. KΩ will be your measurement unit. Remove the fixed resistors from the circuit and determine the value of each using the color bands. Add the values together. Record that total value on your activity page. KΩ will be your measurement unit. How close were the calculated and color band resistance values?

Ohm’s Law Practice Calculating Voltage Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Ohm’s Law Practice Create a series circuit with a DC source and fixed resistors V1 and V2. Calculating Voltage With the power off, use the multimeter to measure the resistance of each fixed resistor. Total resistance will be the sum of each of the measured resistances. Record the resistances, and their sum, on your activity page. KΩ will be your measurement unit. Remove one of the connectors and measure the current with the power on. Record that value on your activity page. mA will be your measurement unit.

Ohm’s Law Practice Calculating Voltage Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Ohm’s Law Practice Calculating Voltage Use Ohm’s Law to calculate the voltage of the circuit. Record that value on your activity page. V (volts) will be your measurement unit. Power the circuit and use a multimeter to measure the voltage drop across each fixed resistor. Add those values to get the total voltage. Record the total voltage on your activity page. mA will be your measurement unit. How close were the calculated and measured voltage values?

Ohm’s Law Practice Calculating Current Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Ohm’s Law Practice Create a series circuit with a DC source and fixed resistors C1 and C2. Calculating Current With the power off, use the multimeter to measure the resistance of each fixed resistor. Total resistance will be the sum of each of the measured resistances. Record the resistances, and their sum, on your activity page. KΩ will be your measurement unit. Power the circuit and use a multimeter to measure the voltage drop across each fixed resistor. Add those values to get the total voltage. Record that value on your activity page. V (volts) will be your measurement unit.

Ohm’s Law Practice Calculating Current Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Ohm’s Law Practice Calculating Current Use Ohm’s Law to calculate the current of the circuit. Record that value on your activity page. mA will be your measurement unit. Remove any one connection and measure the current. Record that value on your activity page. mA will be your measurement unit. How close were the calculated and measured current values?

Answer the conclusion questions on your Activity Sheet!

Ohm’s Law Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Image Resources Microsoft, Inc. (2009). Clip Art. Retrieved January 13, 2009, from http://office.microsoft.com/en-us/clipart/default.aspx