Power Supplies and Transformers Overview

What Is a Power Supply (PSU)?

In the broadest terms, a power supply can be any device that is designed to provide electrical power to a load. Other forms of power can be included to expand the definition, but only electrical power supplies are relevant here.

Power supplies can be regulated or unregulated. Regulated power supplies are used in experimentation and in the actual application of electrical devices. A power supply can refer to anything that fits this role, from the most complex engineer’s desktop power supply to the power supply in the back of a computer to a battery in the handle of a flashlight.


How Does a Power Supply Work?

A power supply takes in input power, in most cases, and changes its parameters or converts it to a different type of electrical current, providing the right type of power for whatever component it is attached to. Power supplies may incorporate a wide range of components to regulate the type of power, the voltage and other characteristics of the power that they supply to the devices attached to them.


What Are Power Supplies Used For?

Power supplies are used in a huge range of applications. In some cases, they are sophisticated devices in and of themselves such as the switched-mode power supplies used to power desktop computers. In other cases, they are very simple devices, such as the wall wart


What Is a Transformer?

A transformer is an electrical component that takes AC current and steps it to a higher or lower output voltage than the current it receives. These are very common devices, available in a wide range of sizes, from exceptionally large devices used in power distribution systems to tiny devices that can be installed on a circuit board.


How Does a Transformer Work?

A transformer consists of two windings, which are wound around a core. These devices use a principal called inductive coupling to transfer the power between the couplings. The current in the primary coil creates flux in the core, which induces current in the secondary winding.


What Is a Transformer Used For?

Transformers are used to isolate circuits, to transform voltage up or down and are used in a vast range of applications. They are found on power poles, in power supplies in the backs of computers and in numerous other applications. They are often used as safety devices, isolating a circuit requiring a low voltage from the full voltage of mains power.

There are adjustable transformers available that are used to supply power to devices and that are used in design and experimentation, as well.


What Are DC-AC Power Inverters?

A DC-AC power inverter is a device that takes DC input power and transforms it to AC output power.


How Does a DC-AC Power Inverter Work?

A power inverter may use various designs to provide AC power, but many of them use a transformer. The transformer is connected to the power at the center tap in the primary winding. The direction of the current is altered through fast switching, providing AC power output. More advanced inverter designs often use transistors as semiconductor switches.

A power inverter can produce various waveforms, including sine and square waves. These are used in specific applications.


What Are DC-AC Power Inverters Used For?

A power inverter is a very useful and versatile device that can be used in a wide range of applications. They include applications for consumer-level use and applications for large-scale industrial use and for power distribution grids.

One of the most common uses for power inverters is taking power provided by a battery and converting it to AC power that can be used in devices that require alternating current. The voltage can be stepped up or down as needed. There are many such devices made to work with 12v DC power, as this is widely available from car batteries and allows the use of AC-powered devices with motor vehicle adapters.

In a power grid, a power converter is often used because it allows power to be transferred with little harmonic content. These devices can also provide a means to shut down power to a damaged portion of the grid that is undergoing repairs.

Uninterruptible power supplies are very common applications for power inverters. They charge up a battery off of mains power and, in the event of an outage, supply that power to whatever devices they’re attached to, usually desktop computers or servers. The inverter converts the battery power to the required AC.

Weapons can even be powered by DC-AC inverters. A common consumer device using this technology is a stun gun. These take low-voltage battery power and convert it to sometimes hundreds of thousands of volts of AC power, which is used to incapacitate people without causing permanent damage.


What Are DC-DC Converters?

These are power converters that receive and output DC power. These are very common in consumer devices, particularly in cell phones. Within a complex electronic device, there are generally several different circuit paths that operate on different voltages. A DC-DC converter provides a means to regulate the power to the correct level for each circuit within the system.


How Does a DC-DC Converter Work?

DC-DC converters may use various means of stepping the power they receive up or down as needed.

A linear converter takes an input voltage and steps it down. These can only reduce voltage. These are not efficient devices, but they are suitable for low-current applications. They can be outfitted with heat sinks that prevent their inefficiency from creating too much heat in the device. They are also able to provide voltage reduction without introducing a great deal of noise into a circuit.

Switched mode converters are more sophisticated than linear converters. They store energy and release it at the proper voltage. They are more efficient than linear converters and can extend the life of battery powered devices. These devices, however, introduce more noise into a circuit than linear converters, making them less suitable for applications where noise sensitivity is a concern.

Magnetic converters use a magnetic field to store and release energy. They may use a transformer or an inductor to accomplish this. They provide good control over the amount of power that they release and they can provide a constant power. They can also be used for isolation purposes when the design incorporates a transformer.

Electromechanical converters are very complex devices that consist of a motor and a generator. The motor and generator may be two separate devices working together or they may be incorporated into one device. They are very flexible and can work with both AC and DC voltage, and multiple phases of electricity.

Capacitive converters use capacitors in their design. These devices allow the current and voltage to be altered. Another term used for these devices is charge pump converters. These are commonly used in high-voltage applications and in low current applications.


What Are DC-DC Converters Used For?

DC-DC converters are suitable for any applications where the voltage of a DC power supply needs to be stepped down. They are also used in applications where one circuit may contain several subcircuits that require different levels of power.

These devices are very commonly seen in battery powered consumer products. Cellular phones, radios and other devices may contain DC-DC power converters. They are also useful for situations where a draining battery may need to provide the same level of voltage to a circuit, where the converter provides a means of regulating that voltage to the proper level. This can enable a device to be run off of one battery instead of multiple batteries, saving space and weight.


What Are Power Conditioners?

Power conditioners can be any of a range of devices and there is no official definition as to what one is. They all function, however, to provide a higher-quality level of power to a device. They may be voltage regulators or other devices that ensure that equipment receives the right amount of power for proper function. They may also be used to provide power that has less noise or to correct power factor.


How Does a Power Conditioner Function?

A power conditioner simply takes line power and converts it to a form that is usable by the equipment to which it is attached. These devices may use various components to isolate the load from the line power and to prevent voltage spikes and other hazards from being sent through the circuitry being protected.


What Type of Applications Use Power Conditioners?

Power conditioners are used in many different applications. They can prevent lights from flickering due to spikes in the power supply. They are also used in devices that protect sensitive electronic equipment. Surge protectors, for instance, prevent computers from receiving large spikes in voltage from lightening striking power lines and from other sources.

Power conditioners may also be used to vary the shape of the wave, the frequency, the impedance and other characteristics of power being fed to an electronic device. They can also prevent damage from undervoltage conditions by preventing the source of power from dropping below a specified level.


What Is Considered Power over Ethernet – PoE?

When a data cable is also used to transmit power to a device, it is considered to be power over Ethernet (PoE). This technology is useful for its capacity to power devices over very long distances. It is also useful for making it possible to reduce the amount of wiring involved in setting up networked systems with many remote, powered components.


How Does Power Over the Ethernet Function?

PoE uses unused connectors on an Ethernet cable to provide the power. Ethernet cables generally have connectors that are not used for the transmission of data, providing an easy way to power the device to which they are attached.


What Type of Applications Use Power over Ethernet?

The uses for PoE are always expanding. Currently, it is commonly used to power sophisticated, networked devices such as VoIP phones. This allows the devices to be set up with only one cable feeding them, simplifying installation.

They are also widely used in security systems. The PoE power can provide a means to power cameras installed in locations where there may be no other source of power available. It can also cut costs by eliminating the need to run separate electrical wiring to such locations.


What Are Renewable Energy Products?

Renewable energy is a term that is defined socially, economically and politically rather than being defined scientifically. Renewable energy products are consumer or industrial products that are designed to run off of power sources such as solar power. A calculator with a solar panel for power, for instance, is a renewable energy product.


How Do Renewable Energy Products Function?

Renewable energy products draw their power from a renewable source—such as light—and convert that to a form of energy useable by the device. This may involve the use of an inverter, power conditioner or other component that adjusts the parameters of the power to make it suitable for the device.


What Type of Applications Use Renewable Energy Products?

Renewable energy products are very popular for applications where mains power may not be available. Solar powered cell phone chargers and other devices are particularly popular, as they allow those devices to be charged without plugging them into a wall socket.


What Are Uninterruptible Power Supplies (UPS)?

A UPS is a device that provides power almost instantly in the event that mains power is removed from a device. They typically consist of a rechargeable battery and an inverter than can change the output voltage to AC.


How Are Uninterruptible Power Supplies Different than Regular Power Supplies?

An uninterruptable power supply is designed to provide power in the event that the main source of power is lost. Power supplies generally stop functioning as soon as their main power source is removed.


What Type of Applications Need UPSs?

UPS systems are used in a multitude of different applications; anywhere suddenly removing the source of power may destroy or damage a device. They are commonly used to provide desktop computers and network servers with a means of staying operational in the event of a power outage.