Mercedes S-class W202

1993-2000 of release

Repair and car operation

Mercedes W202
+ 1.2. The general data
+ 2. Maintenance service
+ 3. Engines
+ 4. Greasing system
+ 5. Cooling system
+ 6. Heating, ventilation
+ 7. Ignition system
+ 8. Fuel system
+ 9. Transmission
+ 10. A running gear
+ 11. A steering
+ 12. Brake system
+ 13. A body
- 14. An electric equipment
   14.1.2. Measuring devices
   14.1.3. Technics of measurements
   14.1.4. Electric equipment checks
   14.1.5. A sound signal
   14.1.6. Replacements of safety locks
   + 14.1.7. The storage battery
   + 14.1.8. The generator
   + 14.1.9. A starter
   14.1.10. The traction relay
   + 14.1.11. Illumination system
   14.1.12. Devices
   14.1.13. The instrument panel
   14.1.14. Lamps накаливания on the panel of devices
   14.1.15. Light switch
   14.1.16. A radio receiver
   + 14.1.17. The aerial
   14.1.18. Dynamics
   + 14.1.19. Rubber brushes of screen wipers
   14.1.20. Jets стеклоомывателя
   14.1.21. Washing atomizers of headlights
   14.1.22. A screen wiper and its engine
   14.1.23. Protect the car
   14.1.24. Anticreeping "immunodeficiency"
   14.1.25. Why headlights grow dull
   14.1.26. "Галогенки"
+ 14.2. Electroschemes

14.1.2. Measuring devices

For measurement of electric parametres in an onboard chain on sale there are so-called combined measuring devices which in one device unite the voltmeter for pressure measurement, the ampermeter for measurement of a current strength and an ohmmeter for resistance measurement.

Measuring devices available on sale differ among themselves mainly with a range and accuracy of measurements. By a measurement range it is established, in what area there should be registered pressure and resistance.

For motorists there are combined measuring devices which are specially intended for carrying out of examinations in the car. By means of such device it is possible to measure frequency of rotation of a shaft in the car, a corner of the closed condition of contacts of the breaker of system of ignition and pressure to 20 Century

At measurement of resistance the device, as a rule, is limited to a range in kiloohms, In addition to it measuring devices are applied to check of electric and electronic elements of a design. They allow to spend wide measurement from small resistance in Ohms up to мегаОмного a range. Very precisely it is possible to measure pressure () that first of all it is required for check of electronic elements of a design.

If it is necessary to check up only, whether pressure (V) the simple control bulb for this purpose approaches () moves in general. However, it is valid only for those electric chains in which there are no electronic details. Nevertheless electronic details extremely sensitively react to too high currents. Under certain circumstances they can fail even at connection of a control bulb.

The prevention

At check of electronic details (transistors, diodes and operating knots) it is necessary to apply the high-resistance indicator of pressure (). It works the same as also a control bulb, however without damage of electronic elements of a design, and approaches for carrying out of all control operations.