Tabla de contenido
Idiomas disponibles
Idiomas disponibles
Voltage and Current in Dual Measurement
When measuring DC voltage and DC current in dual measurement mode, take into account the resistance of the test
lead and internal measuring circuitry. The instrument shares the same common ground both in DC voltage and DC
current measurement. When a current flow through the LO terminal, a voltage drop will occur in the circuit and will
affect the accuracy of the voltage reading.
Considering the internal resistance and external lead resistance total is 0.0125 ohm. If applying a 1 A DC current, an
error of (0.0125 Ω x 1 A) 0.0125 V or 12.5 mV will occur. This error will be relative by range with the ADC dynamic
range of 1.2 V.
The figure below shows an example of measuring voltage and current in secondary measurement mode.
The error in measurement will be significant when applying a higher current.
Resistance Measurement Considerations
When measuring resistance, the test current flows from the input HI terminal through the resistor being measured.
The voltage drop across the resistor being measured is sensed internal to the instrument. Therefore, test lead
resistance is also measured.
The errors mentioned earlier in this chapter for DC voltage measurements also apply to resistance measurements.
Additional error sources unique to resistance measurements are discussed here.
Removing Test Lead Resistance Errors
To eliminate offset errors associated with test lead resistance, refer to Null.
Minimizing Power Dissipation Effects
When measuring resistors designed for temperature measurements (or other resistive devices with large
temperature coefficients), be aware that the instrument will dissipate some power in the device-under-test (DUT).
If power dissipation is a problem, you should select the instrument's next higher measurement range to reduce the
errors to acceptable levels. The following table shows several examples.
Keysight EDU34450A User's Guide
103
Capítulos
Tabla de contenido
