PicoConnect 442, Current Clamps and HFCT Probes: The Pico Probe Ecosystem in India

Probes Are Half The Instrument

The uncomfortable truth about oscilloscope measurement is that the probe matters at least as much as the scope. An Indian power-electronics engineer can buy the best scope on the market and still get rubbish measurements if the probe in front of it is a cheap 1× lead on an SMA-to-BNC adapter. Conversely, a modest PicoScope with the right probe delivers measurements that are dead-on correct because the probe was matched to the signal. This post walks through the PicoConnect 442 probe and the broader Pico probe ecosystem, the smart auto-configuring probes that pair with PicoScope hardware on Indian benches in Bengaluru, Pune, and Chennai: and shows when to reach for each one.

The Pico probe ecosystem has two distinct populations. The first is the PicoConnect smart probe family: auto-identifying probes that talk to the scope through a dedicated interface and tell it what range, coupling, and attenuation to use. The second is the TA-series accessory catalog: traditional BNC-interface probes, current clamps, and sensors that work with any PicoScope input and cover the use cases the smart probes don’t. Both populations matter; both are in the standard Pico product line; both are routinely stocked by GSAS as Pico’s authorized Indian engineering partner.

The PicoConnect Smart Probe Concept

The PicoScope 4444 high-resolution differential oscilloscope is built around a proprietary PicoConnect probe interface. When you plug a PicoConnect probe into one of the 4444’s inputs, the scope reads an identification signature from the probe, looks up the probe’s specifications in its firmware, and automatically configures the input range, coupling, bandwidth, offset compensation, and display scaling. No manual setup. No “oh I forgot the probe was 10× and my measurement is off by 10×” errors. The probe carries its own calibration data and the scope honours it.

This matters because differential probes are notoriously easy to set up wrong. A PicoConnect probe in the hands of a junior engineer works correctly on the first attempt; a traditional unmarked differential probe at 100× attenuation does not.

PicoConnect 441 and 442: The Workhorse Differential Probes

The two PicoConnect differential probes every Indian power electronics bench should have:

• PicoConnect 441: a ±50 V differential probe for general-purpose low-voltage work. Suited for measuring differential signals across shunt resistors, low-voltage motor control outputs, and sensor bridges.
• PicoConnect 442: a higher-attenuation differential probe that delivers 1000 V CAT III isolation per channel when paired with the PicoScope 4444. This is the correct choice for 3-phase mains, high-voltage DC bus measurement, inverter DC-link ripple, and SMPS primary-side measurement where touching the live side with a passive probe would destroy the ground return of the scope.

The CAT III 1000 V rating on the 442 is a system rating, the probe is rated when it is used together with the 4444. It is not a rating on the 4444’s bare input. This distinction matters in India where automotive and industrial test standards (AIS, BIS) increasingly reference IEC 61010 probe categories, and the correct answer is to document the probe + scope pairing in the test procedure.

The practical workflow: plug a 442 into each of the 4444’s four inputs, and you have a four-channel 1000 V CAT III differential capture system for measuring all three phases and the DC link of a traction inverter simultaneously. The 4444’s 20 MHz bandwidth and 14-bit resolution are a good fit for PWM fundamental and first-sideband analysis, power-quality measurement, and inverter commutation characterization.

PicoConnect 415 Passive Probes

The PicoConnect 415 is a passive 1×/10× switchable scope probe in the PicoConnect smart-probe format. It handles the bread-and-butter single-ended measurement that a traditional passive probe covers, logic signals, power rails, single-ended analog, but with the PicoConnect auto-identification advantage. A typical Bengaluru-area SoC bring-up lab running a PicoScope 6000E uses 415 probes for clock, reset, boot-ROM GPIO, and power-good signals; the scope knows the probe is there and the scaling is always right.

TA041, TA042, TA057: Active Differential Probes for Higher Bandwidth

The TA-series active differential probes cover the differential measurement use cases beyond the PicoConnect 442’s envelope, and they work with any PicoScope that has BNC inputs, not just the 4444:

• TA041: 100 MHz active differential probe, 700 V CAT III, 100:1 / 1000:1 attenuation. Useful for general low- to mid-voltage differential measurement on motor drive, protection circuits, and gate-drive analysis where the PicoConnect 442’s 20 MHz bandwidth is not enough.
• TA042: 100 MHz active differential probe, 1400 V CAT III, 100:1 / 1000:1 attenuation. The high-voltage member of the family. This is the choice for SiC and GaN half-bridge measurement on the PicoScope 6000E, where bandwidth above the PicoConnect 442’s 20 MHz is necessary to see the fast switching transients.
• TA057: 25 MHz active differential probe, 1400 V CAT III, 20:1 / 200:1 attenuation. The lower-bandwidth, lower-cost option when 25 MHz is enough for your switching-frequency target (typical IGBT and slower SiC topologies).

The Indian use case that drives TA042 adoption is SiC traction inverter development. The fast SiC edges (kV/µs class slew rates) will smoke a 20 MHz differential probe; the TA042 at 100 MHz has the bandwidth to see them honestly while still rated for the 1000 V class DC-bus voltages a traction inverter runs on. Pair it with a 6000E at 500 MHz or 1 GHz and you have a measurement system that can resolve the gate-drive ring, the miller plateau, and the reverse-recovery tail on a single capture. This is the exact workflow documented in the PicoScope power electronics post.

TA189, TA018, TA138, TA167: Current Probes and Clamps

Current measurement on an oscilloscope is a solved problem, but only if you use the right probe. The Pico TA-series current clamps cover the two bands Indian power electronics engineers actually need:

• TA189: AC/DC precision current probe, 30 A range, Hall-effect-based. This is the “low-current AC/DC” probe, useful for gate-drive current observation, low-side shunt validation, motor sensor current, BMS current draw, and auxiliary rail currents. The DC capability matters for any rail you cannot break the loop on with an AC clamp.
• TA018: AC/DC current clamp, 60 A range, with switchable mV/A output. Sits between TA189 and the higher-current clamps.
• TA138: AC current clamp, up to 200 A range. Practical AC-only choice for motor line current, transformer secondary measurement, and AC mains characterisation where DC capability is not needed.
• TA167: AC/DC current clamp with dual range (200 A / 2000 A). The “traction current” probe, suited for battery main-line current, inverter DC-link current, charger output current, and 3-phase motor line current on the same Pune EV traction bench that uses the 442 differential probes for voltage.

Both clamps are AC/DC, they measure DC current directly, not just AC. This is essential for battery characterization and DC bus monitoring where a pure AC clamp would show zero.

The combination of TA167 + 4444 + PicoConnect 442 is a full power-electronics measurement system on a single bench: voltage (V_dc, V_a, V_b, V_c) on four differential channels, and current (I_dc or I_a) on the TA167 plugged into a BNC input on a second PicoScope. Indian battery OEMs and charger OEMs use exactly this combination for acceptance testing.

TA325, TA326: Flexible AC Current Clamps for High-Current Three-Phase Work

The AC flexible clamp family, TA325 (3-phase variant) and TA326 (single-channel), covers the energy audit and 3-phase monitoring use cases. Both span 30 A / 300 A / 3000 A switchable ranges, which lets a single clamp cover everything from sub-feeder monitoring up to main-incomer three-phase industrial feeders. The flexible Rogowski-style coil opens to clamp around busbars and large conductors that a hard split-core clamp cannot fit on.

These clamps pair naturally with the PicoLog CM3 three-channel AC current logger for facility energy monitoring, and with the PicoScope 4444 for transient capture on heavy three-phase loads. A typical Pune-area EV battery manufacturing facility using the CM3 + TA325 flex clamps for a monthly energy audit is a typical deployment. A typical Chennai-area industrial automation team validating a large motor’s current signature during startup is another. The CM3’s 24-bit resolution means the clamp’s dynamic range is preserved in the logged data, you see inrush current and steady-state current on the same capture without range switching.

HFCT Probes for Partial Discharge

The High-Frequency Current Transformer (HFCT) is a specialized current probe for partial discharge measurement on HV insulation systems. A PD event is a fast, small current pulse in the nanosecond range, an HFCT is a wideband CT (typical bandwidth few hundred kHz to tens of MHz) that passes the pulse through with minimal distortion and lets the scope see it.

HFCT probes are sourced through Pico’s specialist partners rather than being part of the main PicoConnect line, but they are standard accessories for the PD workflow documented in the PicoScope EMC partial discharge post. The common pairing is HFCT + PicoScope 6000E or HFCT + PicoScope 4444, depending on whether you need high bandwidth (6000E) or high resolution for small PD pulses on a noisy background (4444).

A Gujarat solar inverter team uses HFCT on the ground return of an isolation transformer to catch insulation aging. A defence power-electronics team in Hyderabad uses the same probe on cast-resin traction transformer bushings for predictive maintenance.

Thermocouple and RTD Sensors

The Pico sensor catalog extends beyond electrical probes into temperature measurement through two product lines:

• Type K, J, T, R, S, B, N, and E thermocouples for the PicoLog TC-08 8-channel data logger. The TC-08 is 20-bit, USB-powered, and recognises all eight standard thermocouple types. A thermal chamber in a Bengaluru reliability lab commonly runs 8 TC-08s in parallel for 64 thermocouple channels on a burn-in rack.
• Class A PT100 and PT1000 RTD sensors for the PicoLog PT-104 4-channel 24-bit RTD logger. The PT-104 delivers 0.015 °C instrument accuracy for Class A RTDs. This is the instrument for calibrating temperature references, characterizing heat sinks on high-power SiC and GaN modules, and logging thermal runaway tests on Li-ion cells.

The combination of a PicoScope doing the electrical measurement and a PicoLog doing the temperature measurement, both logged to the same laptop with synchronised timestamps, is the pattern for thermal-electrical correlation studies in Pune EV battery labs and Bengaluru SoC thermal labs.

Indian Use Cases: Which Probe Goes Where

Gujarat solar inverter team, AC/DC current + 4444. A TA167 dual-range (200 A / 2000 A) AC/DC clamp on the DC PV input and a TA189 30 A AC/DC clamp on the auxiliary rail, both feeding into a 4444’s BNC inputs. PicoConnect 442 probes on the AC phases for grid-interaction measurement.

Pune EV battery manufacturing, CM3 + TA325 flex clamps. A PicoLog CM3 with TA325 flexible AC clamps on three-phase power to the battery-cycler rack, running continuous energy monitoring over a production shift. Data exported as CSV for the MIS dashboard.

Bengaluru SoC bring-up, PicoConnect 415 + 6000E. Four 415 probes on clock, reset, boot-mode pins, and a DC rail, with the 6000E’s serial decoders capturing the boot ROM UART traffic on a digital channel in parallel.

Hyderabad medical device thermal validation, TC-08 + PT-104 + PicoScope. Eight Type K thermocouples on a device under test for hot-spot scan during a thermal chamber run, two Class A PT100s on the chamber reference, and a PicoScope capturing the device’s current draw synchronously. All three instruments timestamp-aligned through their PicoLog and PicoScope software.

Chennai defence interconnect lab, HFCT + 6000E for PD screening. An HFCT on a cable assembly under HV stress, paired with a 6000E capturing a full 50 Hz power cycle at deep memory. The deep memory lets the engineer see every PD pulse in the cycle without missing any.

Instrument Recommendation

For a power electronics bench doing SiC, GaN, or three-phase work: PicoScope 4444 with four PicoConnect 442 probes plus a TA167 dual-range AC/DC current clamp on a BNC input. Optional TA042 (1400 V, 100 MHz) on a second PicoScope for high-bandwidth switching measurement.

For a battery and cell-characterization bench: PicoScope 4262 or PicoScope 5000D for 16-bit voltage measurement, TA189 for sub-30 A AC/DC current measurement, PicoLog PT-104 for cell temperature, and PicoLog TC-08 for pack-level multi-point temperature.

For an energy audit / facility monitoring rack: PicoLog CM3 with TA325 or TA326 flexible AC clamps spanning 30 A / 300 A / 3000 A switchable ranges to cover sub-feeder up to main-incomer feeders on the same hardware.

Further Reading

• Pico Technology, PicoScope 4444 high-resolution differential
• Pico Technology, Active probes and current probes
• Pico Technology, PicoLog CM3 current logger
• GSAS, PicoScope 4444 product page
• GSAS, PicoLog CM3 product page
• GSAS, PicoLog TC-08 product page
• GSAS, PicoLog PT-104 product page
• GSAS, PicoScope EMC partial discharge and harmonics in India
• GSAS, PicoScope power electronics, IGBT, SiC, GaN
• GSAS, Pico Technology partner page

GSAS Micro Systems is the authorized Indian engineering partner for Pico Technology. Probe selection advisory, accessory kitting, and on-site power electronics measurement support are available from our Bengaluru, Chennai, Hyderabad, Delhi NCR, Mumbai, and Pune offices.