Contents: Test lamp (with needle contact) ↡ LED tester ↡ Universal tester ↡ Voltage measurement ↡ Measuring current ↡ Measuring resistance ↡
Test lamp (with needle contact)
With its help you can check the presence of voltage in the circuit. The brighter the lamp burns, the higher the voltage. The needle pierces the insulation of the wire being tested. The other terminal on the lamp wire is connected to the "ground" (car metal). Note: The test lamp consumes a lot of power, so it is not suitable for testing electronic devices. For this you need a voltage tester with LEDs.
LED tester
Depending on the version, this device shows the presence of direct and alternating voltage between 6 and 700 V. The presence of voltage is visually determined by the lighting of the LED. Simple devices of this type are inexpensive.
Universal tester
This device can measure voltage and current (constant and variable), circuit resistance. Suitable devices with a digital display are also inexpensive these days. Such a device is usually powered by a battery.
Voltage measurement
To measure voltage, for example, at the terminals of a storage battery, connect the negative terminal of the device to the negative terminal of the battery or to the "ground". Connect the positive terminal to the positive terminal of the battery or the wire being tested. If the device shows only 10.4 V, this indicates a short circuit in one of the battery cells. It is also necessary to check the battery voltage when starting the engine with the starter - a value of 5 V indicates a faulty battery.
Measuring current
To do this, you need to connect the device directly to the circuit. During a series of measurements, it is sufficient to disconnect the plug connector and connect a wire between the two contacts.
Attention! Always take into account the threshold values that your tester can measure. The contacts of such consumers as starters or glow plugs carry very high currents, which can damage the device during measurement.
Measuring resistance
In this case, a tester is used to check whether current flows through a particular wire or switch. If the current flows unimpeded, the resistance value will be zero. If there is a break at any point, the resistance value will tend to infinity. In addition, you can find out what internal resistance a particular device has.