Ford Focus>> Electric equipment>> Main concepts>> Measurement of tension, current and resistance
In specialized shops there is a sufficient choice of electric devices. Let's get acquainted with some of them.
Control lamp (with needle contact). With its help you can define, whether there is a tension in this chain. Be careful: the control lamp consumes a lot of energy therefore it is not suitable for check of electronic systems, for example, the control unit the engine. Here tension testers with light-emitting diodes can be applied.
Tension tester with light-emitting diodes. The tester measures tension in a range from 6 to 700 V.Pokazaniya are visible on the digital display. Simple devices are available on sale at the price from 10 euros.
Multimeter — a universal measuring instrument. They can measure tension, a direct and alternating current and resistance. Suitable devices with the digital display are available on sale at the price from 20 euros. Devices have the independent power supply.
Tension measurement
To measure, for example, tension of the storage battery, attach a wire (as a rule, black color) the measuring device with a clip having marking «–», to the negative 31 plug of the storage battery, and a wire with marking «+», (as a rule, red color) — to the positive plug of the storage battery. If the device shows only 10,4 In, it means that one of accumulators of the battery has defect. Check value of tension of the battery during start-up if it makes 5 In, the battery means is discharged.
Current measurement
For this purpose it is necessary for you to interrupt an electric chain. Separate the contact socket and connect the device to contacts. It is necessary to know that such consumer as, for example, the starter uses a considerable current therefore the used device should correspond to a current of a measured chain.
Resistance measurement
By means of a multimeter you can measure internal resistance of electric elements.