EXXOTEST DTM7000, Руководство пользователя

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DTM7000
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Doc.: 00293978-v1
2. THE BASICS OF ELECTRICITY
Reminder of the Basics of Electricity
Voltage. The Volt is used to measure Voltage (also known as 'potential difference' or 'pd), which is
defined as the work done per unit charge in order to move that charge from one point to another. The
symbol used for voltage is V, and its unit is the Volt.
Current. The Amp (or Ampere) is used to measure an electrical current, which is defined as the rate of
flow of electrical charges through a point per second. The symbol used for current is I, and its unit is the
Ampere.
Resistance. The Ohm is used to measure electrical resistance, which is defined as the opposing force
applied, by a component, to the electrical charges in a circulating current. The symbol used for
resistance is R and its unit is the Ohm (Ω).
Physical laws
In an electrical circuit, the flow of current is controlled by the following two rules:

The lower the resistance, the greater the current flowing through the circuit.

The higher the voltage, the higher the current flowing through a fixed resistance.
These two rules allow us to form fundamental Ohms laws:
U=I*R where U is expressed in Volts, R in Ohms & I is in Amperes.
Power is defined by a mathematical formula:
P=I*U where P is expressed in Watts, U in Volts & I in Amperes.
Equipment to be used
The Voltmeter used to measure a voltage or potential difference across the terminals of a component in
an electrical circuit. The following precautions must be taken during use:
The voltmeter must be connected in parallel with the terminals of the component to be tested.
The Ammeter used to measure the current flowing through a circuit. The following precautions must be
taken during use:
 Always connect to the circuit to be tested in series.
 Must be associated with a load.
 Pay careful attention to the maximum authorised current for the ammeter in use.