How Does A Power Supply Work?

We need the power to run various machines and equipment for proper functionality. A power supply is a device that transmits electricity from source to a voltaic load. Its main purpose is to convert current from the origin to the output at right voltage, frequency and electric charges. Other roles of the equipment are regulating the current to loads at safe levels, breaking the charges in cases of short-circuiting and prevention of noise or surge from reaching the load. Supply gadgets have different specifications according to the voltage. There are two main types of 12v power supply, and they work differently. They are the linear and switch mode supply.

12v power supply

How it works

A12V power supply device will decrease the usual 240 volts from the mains to the useable twelve volts required by most appliances/gadgets.


In the linear type, the supply uses a transformer to lessen the voltage. The transformer has both primary and secondary windings. The former joins the mains while the latter connects the output. The most critical thing is the ratio between the primary and the secondary loops. The turns determine the fraction at which the voltage will reduce. The reduction ratio from 240 to 12 volts is normally 20 to 1 (20:1). Hence, when the voltage from the mains passes through the device, the windings reduce it based on Faraday’s law of electromagnetic mutual induction (the electric energy will transform from one value to another).

12v power supply


In the switch method, the device works by swiftly putting on and off the power from the source to minimize the voltage. The spontaneous change happens so quickly. For example, it will happen at approximately ten thousand times per second. The proportion between the on and off time determines the voltage reduction ratio. When the device receives power from the mains, it rectifies and controls the alternating signal (AC) to a direct current (DC)voltage. It then switches it on and off by a field-effect transistor (FET). It then moves to a transformer for the isolation of the output and source electricity for safety purposes. It uses the results from the output to control the ratio thus enabling it to stay at permissible levels like the 12v. The transformer is smaller in this technique but experiences some noise or spikes. This method is highly efficient compared to the linear because it doesn’t produce more heat and is also lighter.


The 12v power supply is an important device that ensures other machines receives current, frequency and voltage at safe levels by a switch or linear means. The former works by using the primary and secondary windings while the latter uses an abrupt on and off switching approach. The switch mode is better because it’s cheap, small, light and efficient.

For more power supply, please check here.

Leave a Reply

Your email address will not be published. Required fields are marked *