In addition to EMI measurement with LISNs (Line Impedance Stabilisation Networks, Artificial Mains Networks), Probes are used for Terminal or Line voltage measurement.
LISNs are required to feed the Equipment under Test (EuT) with mains power, to reduce external line interference, to offer the EuT a standardized impedance and to route the extracted r.-f. voltage to the EMI receiver.
Probes are used for terminal voltage measure ment, also on cables, output sockets, PCB traces. In many cases high input impedance and low capacitance is required for this purpose. Active Probes may not be used for general Interference measurement, as pulses could by far exceed the linear voltage range. This not only causes limiting and distortion effects but also intermodulation that changes the frequency distribution of spectral components.
These resistive dividing probes are perfectly linear and free of these effects.
By the use of an AC and pulse-compatible input blocking capacitor (that is also free of partial discharge effects), EMI measurement is also possible on AC power lines up to 250 V ac or DC sources up to 500 V.
The voltage probe is preferred for applications where the use of LISN is difficult or even impossible due to the high current consumption of the EuT.
The TK 9421 was especially designed for measuring power electronic equipment, e.g. switching power supplies with a strong disturbance spectrum in the kHz-frequency range.
The TK 9422 was especially designed for measuring power electronic equipment, e.g. switching power supplies with a strong disturbance spectrum in the kHz-frequency range.
The voltage probe TK 9261 has been designed for high frequency applications and meets the requirements of the RENAULT 36 00 808 automotive standard. Using shorter RF grounding of the probe, measurements up to 700 MHz are possible.