99% Customer
Satisfaction
Over 10,000 tools shipped across Europe
4.9★ from 1,200+ verified buyers
Trusted by 14,000+ workshops worldwide
Established in 1999
Over 25 years in automotive diagnositcs

TOPDON CT100 Circuit Tester

● In Stock

  • Battery-free circuit tester for 12, 24 and 36 V systems
  • Measures 3.3-65 V DC
  • Built-in load testing up to 1.2 A
  • 3.8 m cable with interchangeable probes

TOPDON CT100 Circuit Tester

The TOPDON CT100 is a circuit tester for 12 V, 24 V and 36 V electrical systems, including cars, trucks and RVs. It measures DC voltage from 3.3 V to 65 V with a resolution of 0.1 V, and carries out load tests from 5 V to 30 V at up to 1.2 A.

A dual-colour backlight shows polarity, red for positive and green for negative, and the tester gives overvoltage and overheat alerts. It needs no batteries, as it is powered from the circuit under test.

The 12.5 ft (approximately 3.8 m) test cable uses 4 mm banana connections, so probes and clips can be swapped to suit the job.

Key Features

  • DC voltage measurement
  • Built-in load testing
  • Dual-colour polarity indication
  • Overvoltage and overheat alerts
  • Battery-free operation
  • Interchangeable 4 mm probes and clips
  • 3.8 m test cable
  • 12, 24 and 36 V systems

Ideal For

  • Automotive technicians checking circuits, voltage and polarity.
  • Workshops working on cars, trucks and RVs.
  • Technicians who need a simple tool for load testing circuits.

In the Box

  • TOPDON CT100 circuit tester
  • 2 mm probe
  • Alligator clip
  • Adapter
  • Carrying bag
  • Quick user guide

Warranty

The TOPDON CT100 is supplied with a manufacturer warranty, subject to the applicable UK warranty terms and conditions.

Warranty claims may require proof of purchase and are subject to the manufacturer’s exclusions, including damage caused by misuse or unauthorised repairs.

For warranty information or assistance with a claim, please contact Maverick Diagnostics with your purchase details.

Product Specifications

Hardware

Product Model
TOPDON CT100
Voltage Measurement Range
DC 3.3-65 V
Voltage Resolution
0.1 V
Voltage Accuracy
u00b10.1 V (3.3-60 V); u00b10.2 V (60-65 V)
Load Test Range
5-30 V
Maximum Load Current
1.2 A
Supported Systems
12 V, 24 V, 36 V (cars, trucks, RVs)
Test Cable Length
12.5 ft (approx. 3.8 m)
Probe Connection
4 mm banana
Polarity Indication
Dual-colour backlight (red positive, green negative)
Protection Alerts
Overvoltage, overheat
Power Supply
Powered from the circuit under test (no batteries)
Operating Temperature
-10 to 50u00b0C
Back to top