600A AC/DC Smart Clamp Meter ( HTC – 21S )

Description

The HTC 21S Smart Digital Clamp Meter is a modern, precision instrument designed for electricians, HVAC technicians, service professionals, and electronics enthusiasts who expect a high level of measurement accuracy and user convenience in a compact tool. Featuring a high-resolution 6,000‑count color LCD display with integrated bar-graph, it delivers immediate visual clarity and detailed numerical feedback for a wide variety of tests. Equipped with True RMS measurement, the 21S offers accurate readings even in the presence of distorted or non-sinusoidal AC waveforms—ideal for measurement in modern electronics and power systems.

Measuring both AC and DC current up to 600 A, the HTC 21S supports two current ranges—60 A and 600 A—with resolutions of 0.01 A and 0.1 A respectively. Accuracy for both AC and DC readings is specified at ±(2.5% + 5 digits), giving high confidence in load measurement across power lines and distribution circuits. The clamp jaw opening is 36 mm, providing flexibility for accommodating conductors of varied thickness without interrupting service.

Beyond current, the meter covers AC and DC voltage measurements up to 600 V across four ranges (600 mV to 600 V). Accuracy is rated as ±(0.5% + 5 digits) for DC voltage and ±(0.8% + 5 digits) for AC voltage, ensuring dependable readings across different test conditions, with a typical input impedance of 10 MΩ.

The 21S also offers full continuity and component testing—including resistance measurement up to 60 MΩ (in auto-ranging steps from 600 Ω to 60 MΩ) with resolutions down to 0.01 Ω and accuracy of ±(1.0% + 5 digits). Continuity mode triggers a buzzer for resistances below 50 Ω, helping to quickly locate short circuits or open circuits. Diode test function indicates forward voltage drop and includes audible feedback.

Capacitance testing spans up to 60 mF, useful for identifying and validating capacitors in electronics or HVAC motors. Accuracy across capacitance ranges is specified at ±(4.0% + 5 digits). Frequency and duty-cycle measurement are supported up to 10 MHz, with frequency resolution from 100 Hz through 10 MHz, and duty cycle range from 1% to 99% at ±(3.0% + 3 digits) accuracy.

One of the standout features of the HTC 21S is temperature measurement using a Type-K thermocouple probe, covering –40 °C to 1000 °C with selectable °C/°F output. Accuracy is rated at ±(1.0% + 3 digits) across this range—making it suitable for motor winding checks, HVAC systems diagnostics, and general thermal assessments.

Safety and operational convenience are core to the 21S design. It provides Non‑Contact Voltage (NCV) detection and Live wire indication, alerting users to energized conductors before probe use. Backlight illumination and a built-in flashlight activated by a trigger switch provide visibility in dim or confined spaces. The device includes practical modes such as Data Hold, MAX/MIN capture, Relative (REL) zeroing, and a DCA Zero function to eliminate background offset for current measurements.

The meter supports both smart auto measurement mode—where it automatically detects the function and range—plus manual mode for deliberate function selection. The display features a digital bar graph for responsive visualization of changes in measurement, while the Low Battery indicator and auto power-off function help conserve batteries. The meter is powered by three AAA batteries and includes overload protection across all ranges for safety and longevity.

Constructed to meet professional safety standards, the HTC 21S is certified to CAT III 600 V IEC safety compliance and EMC protocols under EN 61010‑2‑033 and EN 61326‑1. Its housing provides rugged insulation and handling for serious job site use. Operating environments up to 40 °C and 80% relative humidity are supported, while storage conditions up to –10 °C to 60 °C ensure durability over time.

Physically compact and lightweight, the meter measures approximately 197 × 73 × 34 mm and weighs around 206 g (including batteries), making it highly portable and easy to store in toolkits or belts. The accessory kit includes test leads, TP‑04 thermocouple probe, battery, and user manual, so the device is ready to use right out of the box.

Ideal Applications

Perfect for professionals and enthusiasts involved in:

• Live current measurement and load diagnostics on power circuits

• Voltage testing on AC/DC distribution, control panels, electrical outlets

• Continuity and resistance checks for wiring fault finding

• Capacitance and frequency/duty cycle diagnostics in electronic and motor systems

• Thermal profiling and HVAC inspection through temperature readings

• Safety pre-checks using NCV detection before probing

• Monitoring peak loads using MAX/MIN and REL features for fluctuating signals

In summary, the HTC 21S Smart Digital Clamp Meter combines essential electrical measurement tools and multi-function capabilities in a compact, ergonomic, and highly accurate package. With smart auto-ranging, True RMS sensing, NCV detection, thermal input, and robust safety compliance, it delivers versatility and reliability for technicians across electrical, HVAC, electronics, and industrial maintenance domains.