ADT490Metering Techniques

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Introduction

‣ Alarms ALS390‣ Foundation for Troubleshooting

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Concept Review

‣ Current‣ Voltage

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Concept Review - Conductors

‣ Conductor resistance is American Wire Gage

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Concept Review - Resistance

‣ Depends Primarily on‣ Length‣ Cross-sectional area‣ Type of Material

‣ Conductors DO have Resistance

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Concept Review - Resistor

‣ Limit Current / Divide Voltage / Convert Energy‣ Ohms & Watts

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Series DC Circuits

‣ Current same / Voltage divided between Resistors

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Series DC Circuits - Resistance

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Kirchhoffs Voltage Law

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-

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Voltage Dividers

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Parallel DC Circuits

‣ Voltage in each parallel branch is equal

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Kirchhoff’s Current Law

• For each Junction: Current in = Current out

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Resistance in Parallel

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Resistance in Parallel - Rules

‣RT always < value of smallest resistor

‣ If largest resistor many times smaller resistor‣RT approaches value of smallest resistor.

‣ If two resistors equal‣RT is half original resistance

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Current Dividers

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AC Voltage & Current

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AC Voltage & Current

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Text

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Measuring with a Multimeter

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Using a Voltmeter

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Using a Voltmeter

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Using a Voltmeter

‣ Can use a voltmeter to check a fuse - SAFER

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AC Versus DC

‣ No reading‣ CHECK METER‣ Power on circuit

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AC Versus DC

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Using an Ammeter

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Using an Ammeter

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Using an Ammeter

‣ Fuse in circuit - 0 A fuse good, ? A fuse bac‣ Watch the meter raing

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Measuring Resistance

‣ Voltage impacts on reading - Nonsense Reading‣ Highest to Lowest - Lowest most accurate

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Ohmmeter Uses

‣ Check if EOL is Capacitor - Short then Charge‣ Determine device polarity

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End of Presentation