What is voltage?
The fundamental rules on which any circuit works are voltage, current and resistance. There is capacitance and induction, but we will dwell into them later.
Voltage, denoted by V, is the driving force of any circuit. It is the source of power and is available in different forms. The most common forms are the battery or the adapter. Voltage can be better understood by thinking it as a water pump pumping the water through a pipe. Voltage is measure in volts (V)
Voltage, denoted by V, is the driving force of any circuit. It is the source of power and is available in different forms. The most common forms are the battery or the adapter. Voltage can be better understood by thinking it as a water pump pumping the water through a pipe. Voltage is measure in volts (V)
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| Fig 1. Voltage analogy |
Similar to the water-pump driving the water through the pipes, voltage drives the electron through the circuit. The movement of electrons through the circuit is called current, indicated I. Note that though the electrons move from the -ve terminal of the voltage to the positive +ve terminal of the voltage, current is considered as flowing from positive +ve terminal to -ve terminal. The flow of current through various electronics component causes it to work. Current is measure in amperes (A)
Resistance, as the name suggests, is the barrier to flow of the current. It is indicated by R. A wire has close to zero resistance and air has close to infinite resistance. A thicker wire has relatively less resistance than a thin wire. Resistance is measure in ohms (Ω).
The relation between voltage, current and resistance is explained by the Ohm's law.
$$V = IR$$
$$V = IR$$
Consequently, given any two, it is easy to solve the equation for current. This equation is particularly useful because in most circuits you cannot measure the current. The voltage and the resistance can be measured, so you can calculate the current.
Never connect the voltage in a short circuit. A short circuit means that the resistance is zero. According to the Ohm's law if the resistance is zero, the current will approach infinity and may burn down everything in the path.
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