Fluke 187 user manual Measuring AC Voltage, AC Voltage Measurement

Model 187 & 189

Users Manual

When measuring voltage, the meter acts like a 10 MΩ (10,000,000 Ω ) impedance in parallel with the circuit. This loading effect can cause measurement errors in high- impedance circuits. In most cases, the error is negligible (0.1% or less) if the circuit impedance is 10 kΩ (10,000 Ω ) or less.

Measuring AC Voltage

The meter presents ac voltage values as rms (root mean square) readings. The rms value is the equivalent dc voltage that would produce the same amount of heat in a resistance as the measured voltage. Your meter features true rms readings, which are accurate for sinewaves and other wave forms (with no dc offset) such as square waves, triangle waves, and staircase waves. For ac with dc offset, use $.

Set up the meter to measure ac volts as shown in Figure 3-1.

All pushbutton features are available in this function. The blue button ( %) accesses decibel dBm or dBV) measurements, discussed next in this chapter.

			189 LOGGING MULTIMETER
		AutoHOLD	FAST MN MX		LOGGING	YES
		HOLD	MIN MAX		REL
			CANCEL		SAVE	NO
			Hz % ms		RANGE
		SETUP	nS
		ac+dc mV				F
					C
		ac+dc V				A
						mA
	V	dB mV				A
dB		dB V				A	Switch
						mA
						ac+dc
		OFF				A
							Box
						ac+dc
					VIEW
					CLEAR MEM
						TEMPERATURE
		A	mA		COM	V
			A
		10A MAX		400mA		CAT
		FUSED
				FUSED		1000V
							ach001f.eps

Figure 3-1. AC Voltage Measurement

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