A transformer is an electrical device that achieves voltage conversion as the main function. The transformer is an essential element in electrical devices and systems as it allows power supplied to adapt to power demanded by the machine. One of the classifications of transformer types is on basis of the magnitude voltage it handles. In this, we have high and low voltage transformers. In this read, we will discuss low voltage transformers and specifically the most common types being 24 volts and 12 volts as output.
There are two broad categories depending on design, namely magnetic and electronic types. Electronic types comprise components such as resistors and capacitors. It is light, cheap, less heat dissipation but low lifespan. The most common type is the magnetic type. The design of this type consists of a laminated iron core, shell, or toroidal-shaped magnetic material. The material is a poor conductor of electricity. The primary winding is made of turns of copper wires around the magnetic material. And the terminals connect to the power supply. The secondary winding is made of insulated copper conductors placed in such a way it’s electrically isolated but magnetically linked to primary conductors. The parts may be encased with a plastic or metallic cover for protection against external factors or left bear if it is installed in an already encased device.
Electronic type operates by voltage divider principle. When resistors or capacitors are in a series circuit the voltage across them is proportional to the value of their resistance and capacitance respectively. The output voltage is designed so as to be tapped at the point it is designed. Magnetic transformers work on the principle of Faraday’s electromagnetic induction. The magnetic flux is induced in primary winding when changing current flows, this causes changing flux that is linked to the secondary winding. Changing flux induces an electromagnetic force on the secondary and when the current is closed current flows. Induced secondary voltage is proportional to the turn ratio between the primary and secondary. There is leakage eddy current that flows inside the core because it’s not a perfect insulator, this causes heating and accounts for power losses. The core at the same time is not a perfect soft magnet, reluctance to the flow of flux causes magnetostriction that causes power loss in form of hamming sound and vibration. These transformers their a secondary voltage being 24V or 12V with the primary voltage taking the main supply by the utility power supplier (240Vac or 120Vac). Essentially, it is a step-down transformer. This low output voltage has a myriad of applications in the electronic world.
Electronic devices share one building block, is the transistor. Since the invention of the diode and later transistor, there has been a demand for low voltage power, lower than what the power supplier provides. From computers, mobile phones, digital television, printers among the many digital gadgets have power adapters either inbuilt or external. The power adapter has its first component being a 24 or 12V transformer. The lowered voltage may be handled by other components that further condition the power before being supplied being.