Meter Operation - LTR MT 701 Bedienungsanleitung

5. METER OPERATION

Voltage ( , ) Measurements
Voltage is the difference in electrical potential between two points.
The polarity of ac (alternating current) voltage varies over time, while the polarity of
dc (direct current) voltage is constant over time.
Range available in volts functions are :
400 mV, 4 V, 40 V, 400 V, and 1000V
When measuring voltage, the meter acts like a 10MΩ (10 x 10
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 or less.
Tips for measuring voltage
• In 400 mV range, displayed value may fluctuate when disconnecting input
terminals. This is normal.
32
• To improve the accuracy of dc voltage measurements taken in the presence of
6
Ω) impedance in
Resistance ( Ω ,
(Ohms, Diode, and Continuity)
Resistance is an opposition to current flow. The unit of resistance is the ohm (Ω).
The meter measures resistance by sending a small current through the circuit.
Ranges available in resistance functions are :
400.0 Ω, 4.000 kΩ, 40.00 kΩ, 400.0 kΩ, 4 MΩ, and 40 MΩ
ac voltages (such as, measuring the dc voltage of an amplifier in the presence of
an ac signal), measure the ac voltage first. Note the just measured ac voltage
range and select a dc voltage range that is the same or higher than the ac
voltage range. This method improves the dc voltage accuracy by preventing the
input protection circuits from being activated.
Warning
To avoid the risk of electrical shock and instrument damage,
input voltages must not exceed 1000 V dc or ac (rms). Do not
attempt to take any unknown voltage measurement that may
be in excess of 1000 V dc or ac (rms).
, ) Measurements
To avoid damaging the meter or the equipment under test,
remove all power from the circuit and discharge all high-
voltage capacitors before measuring resistance.
Caution
33