Resistors, Diodes, and Transistors: Part 2 PCB and Components

Resistors, diodes, and transistors are integral parts of a functioning Printed Circuit Board. Without them, a PCB would not be able to perform its tasks. Each of these components has a specific function.


Resistors are a part of a Printed Circuit Board. A resistor creates resistance in the flow of electricity. When calculating resistance the measurements are in ohms. An ohm is a standard for measuring electrical resistance.

Resistors have many different purposes. A resistor’s purpose includes the division of voltage. Resistors divide voltage when they are in series with each other. Another purpose of resistors is their way of generating heat. A resistor can generate heat by converting the electrical energy flowing through it to heat energy. The final purpose that we will describe is how resistors match and load circuits. Most of the output power is displaced as heat in the instance of a too low load resistance. However, if the load resistance is too high then the current will be too low to move energy to the load.

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Diodes only allow current to flow in a single direction. Also, diodes have two electrodes. The anode and the cathode are the two electrodes within a diode. An anode allows current to flow from an outside circuit. Whereas a cathode allows current to flow out in a polarized device. A cathode is also metallic.

A diode only works properly if a cathode is negatively charged in respect to the anode at the specified voltage. Therefore, when a cathode is positively charged the diode does not work at all. This will also happen if the cathode has the same voltage as the anode. It also occurs when its negativity is less than that of the forward breakover voltage with respect to the anode. The direction of the cathode is very important to the diodes functionality.



Transistors are three-terminal devices. This three-terminal device can regulate current or voltage flow while also acting as a switch for signals of the electronic variety. Semiconductors make up three layers of a transistor. Therefore, each of these layers can carry current. The material of a semiconductor is between that of a real conductor and an insulator. A transistor’s job is to amplify or switch electronic signals and electrical power and to regulate the current or voltage flow in a circuit and that is only possible due to the semiconductors.

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Coming Soon: our continuation of our series on printed circuit boards and their components.

Wrapping It Up

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