Topdon CT100 | Circuit tester
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Warranty directly via AsTools
Warranty directly via AsTools
We handle warranty cases ourselves, quickly and without involving the manufacturer. Thanks to our own parts inventory and technical expertise, we can usually assist you immediately. Only in exceptional cases do we still send the product to the supplier.
2 years warranty on all products
2 years warranty on all products
All our products come with a 2-year factory warranty. This ensures you long-lasting quality and service.
Easy returns
Easy returns
You can easily request your return through your account. We will send you the return label by email. Return shipping costs are your responsibility.
Professional customer service
Professional customer service
Our experts are ready to help you quickly and professionally, both online and in our physical store. Questions? Feel free to contact us!
The Topdon CT100 is a circuit tester for diagnosing electrical faults in vehicles. The device features a bright digital display with backlight that shows DC voltage within a range of 3.3 to 65V, with a resolution of 0.1V. Additionally, the tester performs professional load testing up to 1.2A, which checks battery load and circuit load to identify worn batteries, poor connections, and voltage drops. Thanks to its wide measurement range, the tester is suitable for 12V, 24V, and 36V systems in cars, trucks, and motorhomes.
When connected to a circuit, the tester instantly displays polarity via dual-color backlight: red for positive and green for negative, supported by plus and minus symbols on the screen. The extended 3.8-meter test cable reaches hard-to-access locations without needing to move the tester. Via the universal 4 mm banana connectors, interchangeable probes and clamps can be used. The tester operates without a battery thanks to power from the circuit being tested, with built-in protection against overvoltage, overheating, and reverse polarity to safeguard sensitive vehicle electronics.
KEY FEATURES
THINGS TO NOTE
Application and functionality
The CT100 supports the following electrical testing functions:
- DC voltage measurement: Measures DC voltage from 3.3 to 65V with 0.1V resolution, for checking batteries, sensors, and power supplies.
- Load test: Draws up to 1.2A from the circuit to assess actual load capacity and reveal weak points.
- Polarity check: Displays instantly via red or green backlight whether a connection is positive or negative.
- Fuse test: Checks continuity and voltage on fuses without removing them from the fuse box.
- Wiring diagnosis: Traces breaks, short circuits, and voltage drops in vehicle wiring.
- Connector check: Verifies voltage on connectors and plugs when troubleshooting starting issues or intermittent faults.
What's in the box
- 1x Topdon CT100 circuit tester
- 1x 2 mm measurement probe
- 1x Alligator clip
- 1x Adapter
- 1x Carrying case
- 1x Quick start guide
Technical Specifications
| Specification | Description |
|---|---|
| Brand | Topdon |
| Model | CT100 |
| Type | Circuit tester with load testing |
| Display | Digital display with dual-color backlight |
| Power Supply | Battery-free, powered by the circuit being tested |
| Compatible With | 12V, 24V and 36V systems |
| Voltage Measurement Range | 3.3V to 65V DC |
| Load Testing | 5V to 30V, maximum 1.2A |
| Measurement Accuracy | 3.3V to 60V: ±0.1V · 60V to 65V: ±0.2V |
| Measurement Resolution | 0.1V |
| Polarity Indication | Red light for positive, green for negative |
| Protection | Overvoltage, overheating and reverse polarity |
| Probe Connection | 4 mm banana plug |
| Cable Length | 3.8 meters |
| Operating Temperature | -10°C to 50°C |
| Storage Temperature | -20°C to 70°C |
| Part Number | CT100 |
