USB oscilloscope offers four differential input channels

23rd March 2017

Mick Elliott

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Datasheet

The PicoScope 4444 High-resolution Differential Oscilloscope from Pico Technology which features four true differential input channels and a range of accessories for measurements from millivolt to 1000 V CAT III applications is available at Saelig. It has been designed specifically for making accurate voltage waveform measurements on circuits that are not ground-referenced, avoiding the dangers of equipment damage due to short circuits.

The oscillioscope can facilitate differential voltage measurements in the presence of common-mode signals, with 14-bit resolution and 20MHz bandwidth on all four differential channels and 256MSa waveform capture memory.

It is ideal for the precise analysis of complex waveforms ranging from biomedical sensors to current probes and 1000 V CAT III power distribution circuits and it offers a choice of complementary 1:1 low-voltage and 25:1 1000V CAT III probes to address these and other situations.

The oscilloscope has an intelligent probe interface that can provide power for a wide range of PicoConnect voltage probes, current probes such as Hall effect DC/AC, and Rogowski coil type active current probes.

It automatically detects when a compatible probe is connected and sets the corresponding units and vertical settings in the supplied PicoScope 6 software. The USB-powered PicoScope 4444 is available in two kits that include key accessories.

These are the PicoScope 4444 Standard Differential Oscilloscope Kit, consisting of a PicoScope 4444, three differential 1:1 probes and one TA271 BNC single input adaptor and the PicoScope 4444 1000 V CAT III Differential Oscilloscope Kit, consisting of a PicoScope 4444, three 1000 V CAT III 25:1 differential probes and one BNC input adaptor.

Scientists and electronics engineers frequently need to make low-voltage measurements in the presence of high common-mode noise or varying offset voltages.

Ground-referenced oscilloscopes require the use of two input channels and an A-B math function to observe the differential signal of interest.

But, in addition to requiring two input channels, most scopes don't have a high enough common-mode rejection ratio (CMRR), nor the resolution to make measurements with sufficient precision.

Engineers working on polyphase power distribution systems need to measure phase-to-phase AC voltages, rather than phase to ground.

A ground-referenced scope can't be used as it will cause a short circuit. External differential probes are a solution but they are quite expensive and cumbersome, with each probe requiring its own power supply.

The PicoScope 4444 provides the solutions for each of these situations, but it can also be used as a general purpose scope with all the useful features that PicoScope software provides - such as serial bus decoding, mask and limit testing, math channels and automatic measurements.