CT4066: Active Differential Probe 25 MHz 20x/50X/200x, ±70 V/±175 V/±700 V

Click Images For Larger Photo

Cal Test Electronics CT4066 25 MHz Differential Probe Photo Cal Test Electronics CT4066 25 MHz Differential Probe Photo

The CT4066 differential probe allows safe, accurate measurement between two voltage points where neither point is referenced to ground. The probe offers both a 25 MHz bandwidth for the 50x and 200x attenuation settings and a 15 MHz bandwidth for the 20x attenuation setting. Compatible with oscilloscopes from all major manufacturers, the probe is exclusively powered by the included 9 V power adapter.


  • Meets IEC 61010-031 safety standard
  • Selectable attenuation settings of 10x/100x
  • 25 MHz bandwidth (at 50x/200x attenuation settings)
  • 15 MHz bandwidth (at 20x attenuation setting)
  • Up to ±700 V differential
  • High accuracy (±2%)
  • Power and over range indicator LEDs

Comes with:

  • (2) Pincer Clips, black & red
  • (2) Alligator Clips, black & red
  • (2) Sheathed 4 mm banana plug test leads, silicone jacketed, black & red
  • Insulated BNC cable, 100 cm
  • 9 V Power adapter included (CT3957)

Electrical Characteristics
Bandwidth (-3dB)

25 MHz for 50x/100x

15 MHz for 20x

Rise Time (probe only)

14 ns for 50x/100x

23.4 ns for 20x

Attenuation ratio 20x/50x/200x
Accuracy ±2%
Input Voltage:  
Differential Input Voltage (DC + AC peak) @ 20x ±70 V
Differential Input Voltage (DC + AC peak) @ 50x ±175 V 
Differential Input Voltage (DC + AC peak) @ 200x ±700 V
Absolute Maximum Rated Input Voltage (each side to ground) 600 Vrms
Input Impedance 4 MΩ // 1.2 pF 
Input Impedance (each side to ground)  2 MΩ // 2.3 pF
Output Voltage:  
Swing ±8 V (driving 1 MΩ oscilloscope input)
Offset (typical) ±5 mV
Noise (typical) 2 mVrms
Source Impedance (Typ.) 50 Ω
Safety Specifications IEC 61010-1 CAT II
Mechanical Characteristics
Weight 250 g
Dimensions 195 x 55 x 30 mm
BNC Cable Length 100 cm
Input Leads Length 55 cm
Environmental Characteristics
Operating Temp/Humidity 0°C to 50°C / Up to 85% RH
Storage Temp/Humidity -30°C to 70°C / Up to 90% RH
Pollution Degree Pollution Degree 2
Model # MSRP (ea.) Where to Buy
CT4066 $330.00