Welcome to the second post in our series that explains what is going on under the hood of most of the electronics you use. In the last blog, we defined a circuit, spoke about important circuits, and outlined a critical circuit component, a capacitor. Let’s dive right in and look at resistors:
Resistors also work with circuits.
- A resistor is a passive two-terminal component (it has a positive side and a negative side) that resists the flow of current. It is one of the most common circuit components because resistance is integrated into almost every electronic circuit.
- Resistance is a natural property that almost all conductors possess. It is comprised of a copper wire wrapped around an insulating material (a material that does not conduct electricity). The thinness of the copper wire is directly proportional to the resistance. The thinner the wire, the higher the resistance.
- A resistor provides the vital function of controlling the voltage and current in your circuit.
- Resistors are added to the circuit to prevent the current from flowing at dangerously high levels. Resistors prevent overheating.
- Resistors also reduce the voltage to the level you desire. Say a microcontroller in a circuit needs a lower temperature than the circuit itself – a resistor comes in handy here.
- Resistors are used conjunctively with capacitors to build Integrated Circuits containing resistor-capacitor arrays in one chip. These are known as RC filters or RC networks, and they are used to suppress radio frequency interference or electromagnetic interference in a variety of devices.
- Diodes are another component commonly found in circuitry
- A diode is a device with two terminals that only allows electric current to flow in one direction. It’s commonly used to convert alternating current (electricity that goes in two directions) into direct current (electricity that only goes in one direction). Most diodes today are made from silicon.
- Diodes might be one of the simplest parts of a circuit, but they have unique applications.
- The most common application is changing AC power to DC power. You can combine diodes and capacitors to build voltage multipliers – you can multiply a small AC voltage into high DC outputs.
- Diodes can be connected across inductive loads to help protect equipment damage. When the power supply to an electronic suddenly gets interrupted, it produces a high voltage spike, which can damage the loads. The electricity could easily flow through the Diode and go out in the same direction,
- Diodes are also used for signal modulation because they can remove the negative element of an AC signal, turning it into DC. You’ll commonly find diodes in radios.
- Diodes offer reverse current protection. Incorrectly connecting the battery can send s surge of current through a circuit. This can damage the connected load. This is why a protective diode will be connected in line with the positive side of the battery terminal. If a wrong connection occurs, it will block the current, protecting your equipment from potential damage.
This is one of the most critical parts of an electronic circuit. Transistors are tiny semiconductor devices with three terminals, used as amplifiers and switching devices. They can turn something “on” or “off” without any movement.
- Each transistor has three pins: base, collector, and emitter.
- Transistors will often be used as a switch because it can turn a small current into a larger one.
- In computers, transistors make up something called logic gates, the lifeline of computer programs.
- A transistor is sort of like an extension of diodes. In a way, they are just two diodes with their cathodes tied together.
- The diode connecting base to emitter shows you which way current is intended to flow through the transistor
- Transistors are built by stacking three different layers of semiconductor material together. Some of these layers have extra electrons, while others have electrons removed. A semiconductor material with extra electrons is called an n-type, and a material with electrons removed is a p-type. You create transistors by stacking an n on top of a p, or a p over n over p.
- Transistors are kind of like an electron valve. You might adjust the base pin to allow more or less electrons to flow from its emitter to collector.
So far, we’ve covered circuits, and the following circuit components: capacitor, resistor, diode, and transistor. We’ll be covering even more circuit components in part three – by the end of these series you’ll be an electronics expert!