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Electric currents flow along wires to transmit energy for domestic and industrial purposes. To understand many electrical phenomena, it is only necessary to learn a few simple rules of circuit analysis and these will be the underlying theme of this section on VU2.IN.
- Voltage - also termed as potential difference. Represented by letter V
- Current - Amount of electron flow. Represented by letter I
- Resistance - The fundamental force that opposes flow of current. Represented by letter R
Voltage
Voltage is commonly used as a short name for electrical potential difference. In this introduction, the term "voltage" is however used to mean electric potential, i.e. a specific value (not a difference), and is denoted by the symbol V. The SI unit for voltage is the volt (symbol: V). An older name for "voltage difference" is "potential difference (P.D.)". This name seems to be dropping out of use, possibly because science has no accepted name (other than "voltage") for the potential in question, which is defined as (−μ/e).
The various voltages in a circuit can be computed using Kirchhoff's circuit laws and Voltage is additive in nature.
Voltage is measured by Voltmeter, and now you have DMM (Digital Multimeter) to assist you to measure AC or DC voltage in a circuit.
Current
The Electric current is the flow of electric charge. The electric charge that flows is carried by, for example, mobile electrons in a conductor, ions in an electrolyte or both in a plasma.
The SI unit of electric current intensity is the ampere (symbol: A). Electric current is measured using an ammeter. DMM's can measure current for you as well when connected in series and when the probes are in appropriate sockets.
Resistance
The electrical resistance of an object is a measure of its opposition to the passage of a steady electric current. An object of uniform cross section will have a resistance proportional to its length and inversely proportional to its cross-sectional area, and proportional to the resistivity of the material. Denoted by symbol R in electronic circuits, it denotes is the resistance of the object, measured in ohms Ω.
In any electronic circuit Voltage, Current and Resistance are related to each other by Ohm's law as
V=I x R
Hope you have found it interesting so far, in the next topic we would discuss few law's governing electronic circuits namely Ohm's Law and Kirchoff's Law
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