Electrical Components

Here's a post that's mostly for my own studies, but I hope others will find it useful. Today, we're studying electrical components and their functions.

Resistors control the flow of electrons (current, I) through a medium. Resistors are rated in terms of resistance in Ohms. A variable resistor is called a potentiometer or pot.

Capacitors store energy. Capacitors are rated in terms of Farads (F) such as picofarads (pF) or microfarads (uF). They smooth out changes in voltage and are compared to a water tower. A water tower stores water and serves it to the community until it slowly runs out of water or until more water is pumped into it. The same goes for capacitors and electrons. Capacitors have no effect on AC current since it will be constantly filling and emptying as the current changes directions.

Inductors store magnetic energy like a capacitor stores electrical energy. Inductors are rated in terms of Henries (H) such as millihenries (mH). They smooth out changes in current (capacitors smooth voltage changes). When current is placed onto an inductor, the coil forms a magnetic field that builds until it reaches the max inductance for the inductors. The inductor then releases current at a steady rate.

Resistance to AC current is called reactance (signified by X) and is measured in Ohms. Capacitors are said to have capacitive reactance; inductors are said to have inductive reactance. The combination of capacitance and reactance is generally referred to as impendence.

Diodes allow current to flow in only one direction. If AC current is applied to a diode, the result is a DC current.

Transistors are doped so that small changes in voltage or current control larger voltages and currents. In other words, they can act as amplifiers if patterned correctly.

Integrated circuits (IC or chip) are combinations of active and passive components packaged together to do a particular task. Microprocessors are ICs.

Fuses interrupt excessive current by physically breaking the connection. Breakers do the same, but, instead of blowing up or melting, they trip and can be reset.

Ground-fault interrupters (GFIs) trip of it senses a current difference between hot and ground. If you drop the hair dyer in the tub, the ground side of the GFI will have a drop in current (since all the electrons are pouring out into the water), and the GFI will trip.

Surge protectors become resistors if the voltage gets above a certain level. This eliminated transient spikes. Lightning arrestors do the same job as surge protectors but are designed to take much higher currents and voltages.

Schematics are diagrams that describe a circuit. They use circuit symbols that represent the components and how they are connected together. Each symbol has a designator to name each component, like R1, R2, R3, RN for the resistors.