Dc Voltage Measurements; Operating Instructions - Extech Instruments 411 User Manual

Operating Instructions

WARNING: Risk of electrocution. High-voltage circuits, both AC
and DC, are very dangerous and should be measured with great
care.
1. ALWAYS turn the function switch to the OFF position when the
meter is not in use.
2. If "1 " appears in the display during a measurement, the value
exceeds the range you have selected. Change to a higher range.
NOTE: On some low AC and DC voltage ranges, with the test
leads not connected to a device, the display may show a random,
changing reading. This is normal and is caused by the high-input
sensitivity. The reading will stabilize and give a proper
measurement when connected to a circuit.

DC VOLTAGE MEASUREMENTS

CAUTION: Do not measure DC voltages if a motor on the
circuit is being switched ON or OFF. Large voltage surges may
occur that can damage the meter.
1. Set the function switch to the
highest V DC (
2. Insert the black test lead banana
plug into the negative COM jack.
Insert the red test lead banana
plug into the positive V jack.
3. Touch the black test probe tip to
the negative side of the circuit.
Touch the red test probe tip to the
positive side of the circuit.
4. Read the voltage in the display.
Reset the function switch to
successively lower V DC
positions to obtain a higher
resolution reading. If the polarity
is reversed, the display will show
(-) minus before the value.
) position.
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