Digital Multimeter Introduction Choosing the right meter Category Category ratings are designed to protect users from transient overvoltage conditions (intermittent voltage spikes caused by electrical equipment surges during starting, capacitors, inductive circuits, and lightning strikes) It is these unintended and intermittent transient voltage spikes that can be dangerous to users with too low of meter category rating

Digital Multimeter Introduction Choosing the right meter Category With the likely hood of working in multiple different category environments always choose a meter that will be safe for working on the HIGHEST category that could potentially be accessed Choose a Steady State Voltage rating that meets the maximum voltage you will encounter ALWAYS choose the Category FIRST and then a steady state voltage value A CAT III–600V meter will provide far superior transient voltage protection than CAT II–1000V meter

Digital Multimeter Introduction Choosing the right meter Category TEST LEADS: Be sure your test leads have an equal, or HIGHER, Category and Voltage rating than the chosen meter Meter system only as-good-as its components (as strong as the weakest link) Quality Leads should be rated CATIII 1,000V and CAT IV 600 and UL Listed Double insulated

Digital Multimeter Introduction TEST LEADS: Protective tips and accessory clips make connecting to circuits and components easier and safer, but change the category rating of the test leads. With Protective tips: 1000V CAT III & 600V CAT IV WithOUT Protective tips: 1000V CAT II & 600V CAT III (LOWER Rating)

Review for Understanding What are the two types of signals commonly converted and displayed on a DMM? True of False: DMMs can measure a wide range of signals with accuracy. How many ohms is 92.2 kΩ Explain the 4 basic operations DMMs help us to perform. Define High Impedance. Why is it important when testing electronic circuits? Answers Rapid electrical pulse signals & Steady state or Slow Changing signals True 92,200 Convert Electrical Signals into Understandable Values Perform highly accurate electrical measurements Solve electrical equation calculations Enable testing of sensitive electronic circuits High impedance is high resistance and limits the amperage draw from an electronic circuit to protect it.