
Oscilloscope / Differential Probe Selection
Selecting the correct oscilloscope probe ensures accuracy and can improve the performance of your test instrument. TPI offers a wide range of high quality oscilloscope probes designed to meet the most demanding applications.
The IP series monolithic probes have switchableattenuation and are available in 60 and 250MHz. Theseprobes are ideal for technicians that need a basic oscilloscopeprobe.
The slimline design P and SP series probes are available in fixed or switchable attenuation.These series of probes are perfect for the technician needing additional features such asreplaceable cable and interchangeable probe tip. The compensation adjustment for these probesis located in the BNC to eliminate noise pickup.
TPI also offers three models of high voltage differential probes all with high common moderejection, wide bandwidth, and fast rise times. Differential probes enable the viewing of signalsnot referenced to earth ground and provide better performance than a matched pair of singleended oscilloscope probes when measuring these types of signals.
Several important factors must be taken into account when selecting the proper probe.
Oscilloscope / Differential Probe Terminology
>>Attenuation: Ratio of the output signal to the input signal. Attenuation should remain constant decreasing by 3dB only as the frequency increases to the maximum bandwidth.
>>Bandwidth: The maximum -3dB frequency that can be expected.
>>Cable Length: Length of the cable from the end of the probe to the end of the connector. It is important to use a probe with just enough cable length for your needs. Long cables increase the capacitance and propagation delay of the probe.
>>Compensation Range: The range a probe can be compensated to match the input capacitance of the test equipment it is being used with.
>>IEC 1010: Probes with the IEC 1010 category rating have been designed for safety.
>>Input Impedance: The total resistance and capacitance as measured at the tip of the probe. This specification is used to define the loading effect of a probe. At frequencies under 1MHz the input resistance of the probe will have the most influence. At higher frequencies the input capacitance will have the most influence.
>>Max Input Voltage: The maximum voltage the probe can be used at.
>>Max Differential Voltage: The maximum differential voltage that can be measured by a differential probe.
>>Readout: Probes with this capability are compatible with readout function oscilloscopes that automatically detect and display the attenuation factor of the probe.
>>Rise Time: The time required for the leading edge of a pulse to rise from 10% to 90% of its final value.
>>CMRR: Common Mode Rejection Ratio. A measure of a differential probes ability to reject any signals common to both test points in a differential measurement.
FUNCTION | ADF25 | ADF25A | ADF25C |
|---|---|---|---|
Bandwidth | DC -25 MHz (-3dB) | DC -25 MHz (-3dB) | DC -70 MHz (-3dB) |
Accuracy | ± 2% | ± 2% | ± 2% |
Rise Time | 14nS | 14nS | 14nS |
CMRR (Typical) @ 50Hz | -80dB | -86dB | -80dB |
CMRR (Typical) @ 20kHz | -60dB | -66dB | -60dB |
CMRR (Typical) @ 200kHz | -50dB | -56dB | -50dB |
Input Impedance | 4M/10pf each side to ground 8M/5pF between inputs | 4M/10pf each side to ground 8M/5pF between inputs | 10M/10pf each side to ground 20M/5pF between inputs |
Input Voltage | ±140V DC Inc.Pk AC @ 20:1 or 100V RMS | ±170V DC Inc.Pk AC @ 10:1 or 50V RMS | ±700V DC Inc.Pk AC @ 100:1 or 400V RMS |
Maximum Differential | ± 1,400VDC Inc. Pk AC 200:1 or 1,000V RMS | ± 1,400VDC Inc. Pk AC 100:1 or 500V RMS | ± 7,000VDC Inc. Pk AC 1,000:1 or 5,000V RMS |
Output Voltage | ± 7V minimum 2KΩ load | ± 7V minimum 2KΩ load | ± 7V minimum 50KΩ load |
Offset (typical) | <± 5mV -10° C to + 40° C | ||
Common Mode | ± 1,400V DC Inc. Pk AC or 1,000V RMS | ± 1,400V DC Inc. Pk AC or 1,000V RMS | ± 7,000V DC Inc. Pk AC or 2,500V RMS |
Noise (typical) | 0.7mV RMS | 0.7mV RMS | 0.9mV RMS |
Output Source Impedance | 1Ω @ 1kHz. 8Ω @1 MHz | 1Ω @ 1kHz. 8Ω @1 MHz | 50Ω |
Operating Temperature | -10° C to + 40° C (14°F to 104°F) | ||
Power Requirements | 4 AA cell or 6V main adapters: DC/600mA or DC/800mA | ||
Power Supply | Not included | ||
Input Leads | 45 cm double insulated PVC terminated in 44 mm safety plugs | 45 cm double insulated PVC terminated in 44 mm safety plugs | 60 cm double insulated Rubber terminated in sprung hooks |
IEC1010 | CAT III | CATIII | CATII |
