CT6904A/ CT6904A-1 – AC/DC Current Sensor


Best-in-class Measurement Bandwidth with High Accuracy


CT6904A – AC/DC Current Sensor, Cable length: 3 m (9.84 ft.)
CT6904A-1 – AC/DC Current Sensor , Cable length: 10 m (32.81 ft.)


Hioki’s pass-through type AC/DC current sensors can be connected directly to Hioki Power Analyzers and Memory HiCorders. Also, it can be connected to Power Meters, Oscilloscopes, DMMs, etc. by using an optional sensor unit.

The CT6904A has a frequency bandwidth of DC to 4 MHz (Model CT6904A-1 is DC to 2 MHz) and a rated current of 500 A. It is used in research and development fields such as loss measurement of high-frequency reactors, wireless charging systems, and EV inverter motors.

Use with an instrument with a high input impedance of 1 MΩ or higher.

Key Features

  • Super high accuracy (amplitude): [DC]±0.032%, [50 Hz/60 Hz]±0.027 %
  • Super high accuracy (phase): [50 Hz/60 Hz]±0.08°
  • 500 A (rms) rated for measurement of large currents
  • CT6904A: DC to 4 MHz (±3 dB), CT6904A-1: DC to 2 MHz (±3 dB) wide measurement frequency range
  • ±5 ppm excellent linearity
  • 120 dB (100 kHz) high Common-Mode Rejection Ratio (CMRR)
  • ±0.057% power accuracy in combination with the Hioki Power Analyzer PW8001 (When using U7005)
Rated current 500 A AC/DC
Max. allowable input Within the derating range, However, up to ±1000 A peak is allowable if within 20 ms. (design value)
Frequency bandwidth Amplitude: DC to 4 MHz (CT6904A), DC to 2 MHz (CT6904A-1)
Phase: DC to 1 MHz
Linearity ±5 ppm Typical (23°C (73°F))
Offset voltage ±10 ppm Typical (23°C (73°F), no input)
Basic accuracy DC (Amplitude: ±0.025 % rdg. ±0.007 % f.s., No phase specification)
45 Hz ≤ f ≤ 65 Hz (Amplitude: ±0.02 % rdg. ±0.007 % f.s., Phase: ±0.08°)
Output voltage rate 4 mV / A rated (This device outputs AC+DC voltage via the Sensor Unit)
Max. rated voltage to earth 1000 V CAT III
Core diameter φ 32 mm (1.26 in)
Operating temperature, humidity -10°C to 50°C (14°F to 122°F)
80% RH or less (with no condensation)
Power supply Power suppled via the Power Analyzer PW8001, PW6001, PW3390, or Sensor Unit CT9555, CT9556, CT9557
Max. rated power 7 VA Max. (500 A/55 Hz measurement, with a power supply of ±12 V)
Dimensions and mass 139 mm (5.47 in) W × 120 mm (4.72 in) H × 52 mm (2.05 in) D
CT6904A: 1.05 kg (37 oz), cable length 3 m (9.84 ft)
CT6904A-1: 1.35 kg (47.6 oz), cable length 10 m (32.81 ft)
Included accessories Instruction Manual ×1, Carrying case ×1, Color labels (for channel identification) ×1, Operating Precautions ×1