A resistor is a passive two-terminal electrical piece that gears electrical resistance as a circuit element. The role of resistors is to help reduce the current flow while lowering the voltage levels within circuits.

There are different types of resistors. The production of every form of the resistor depends on its characteristics and accuracy that will fit a specific application. The purpose could vary according to High Stability, High Voltage, High Current, and others. Hence, resistors can also be for general use.

The common characteristics of a resistor:

Temperature Coefficient
Voltage Coefficient
Noise
Frequency Response
Power and Temperature Rating,
Physical Size
Reliability

Resistors are also called as “Passive Devices“because they contain no source of power or amplification; however, the device will only mitigate and decrease the voltage or current signal passing through them. The attenuation of voltage is happening because of the lost electrical energy in the form of heat.

Resistors are made in a variety of shapes and sizes. They may be installed through hole or surface-mounting. A resistor can also be in a standard, static, a pack of resistors, or a special-designed resistor.

Why need Resistors in an electric circuit

The primary function of a resistor is to limit the current passing to a safe value on order for the sophisticated parts of a device or system can function correctly. It opposes the flow of the current through it. The strength of opposing the current flow is called the resistance.

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The circuit arrangement of Resistors

Series installation

If the installation of the resistors is in series type, the resistors are functioning as a network the divides the passing voltage. In a series circuit where the current is flowing through the resistor are all on the same value. But the voltage that is present for each resistor is receiving part of the total voltage that the circuit is receiving from the source.

Parallel installation

When a resistor is in a parallel system, it can be said to a network that divides the current flow. In a parallel circuit, the voltage traveling across each resistor is in the same value. However, the current flowing in each of the resistors only part of the total amount of the current flowing in the circuit.

Functions of Resistor

Transistor Biasing

Typically, a transistor will need a small base voltage to allow the large voltage to flow through the emitter terminals. However, the base of the transistor is vulnerable to high current. Therefore, placing a resistor will limit the current and provide a safe biasing voltage.

LED Current Limit

LEDs are susceptible whenever high currents occur. Placing a resistor in series with the LED will regulate the flow of the current.

Resistor in Timers

In Timing Circuits

The timing components in timer and oscillator circuits with a resistor and a capacitor. With this, the time to take to charge or discharge a capacitor will constitute time pulses or trigger for the circuit. The resistor effectively controls the charging and discharging process. The value is varied to achieve appropriate different time intervals.

Surge Protection

In most cases, when you initially switch ON the power supply, it typically inflicts a power surge that could be dangerous. The critical components of the electronic circuity can experience damage. When a resistor is installed in a series circuit, the resistor can check and manage the sudden rise of voltage.