The Definition of Power Supply

A power supply is an electrical device that provides an electrical current to a load. It is also known as an electric power converter and can be either a separate load or fabricated into an appliance. It can provide voltage and current that is tailored to the demands of a specific load. There are several types of power supplies.

Overvoltage protection

Overvoltage protection is an important component of any power supply and is critical to the safety of your electronic equipment. Overvoltage can result in damaging spikes of current that must be detected and diverted away from your equipment. Overvoltage events can also occur from non-power supply failures such as user errors, short circuits, and switch errors. Regardless of the cause, it is essential that the protection circuit can differentiate between normal voltage fluctuations and transient events.

The best way to protect electronics from the harmful effects of electrical overvoltage is to use a transient voltage suppressor. These are commonly used in electronic appliances and are comprised of a large junction Zener diode or metal-oxide varister. These devices have fast response times and high pulse-power capabilities. They can also prevent the damage caused by output-voltage spikes in power supplies.

Overvoltage protection is important because it monitors the voltage level in power supplies and can take appropriate action to return the system to good operating conditions. This can include generating an alarm or trip circuit breakers. It can also monitor phase-to-phase and phase-to-neutral voltages. This type of protection is important for the safe operation of your installation, particularly in the case of critical situations.


Noise is a common characteristic of power systems, whether electrical or electronic. It can come from a variety of sources, including switching surges and lightning. It can also be internal, due to faults in the switchgear or wider electrical design. Noise is also created externally, due to electromagnetic interference from currents in the cables or equipment. It can disrupt circuit operation and damage equipment.

Noise is generally undesired periodic or random, and can interfere with the performance of a device. In order to minimize the effect of noise, it is often best to isolate the noise from the rest of the system. However, chasing the absolute minimum in noise is a case of diminishing returns. It is therefore better to match the spectral output of a device to that of the power supply. This knowledge will help reduce the risk of over-engineering and save design time.

The most common source of noise is power/ground noise. Power/ground noise is a transient effect, and it is usually caused by currents drawn by switching devices. This reduces the voltage in the power delivery network, which affects all connected devices. Some power saving techniques also exacerbate this problem by causing large inrush currents.

Voltage regulators

Voltage regulators limit the output voltage by changing the resistance of the load. This change can be gradual, or sudden. Most regulators feature built-in over-current protection, which prevents the output current from going too high. Some regulators also shut down if the input voltage is outside a certain range.

One type of voltage regulator uses two field coils, one fixed and one movable. The movable coil is connected to a mechanical power switch, which is opened or closed when the magnetic field is high. Usually, the switching rate of a voltage regulator is fifty to 200 times per second.

Voltage regulators also use feedback to reduce the voltage error. This form of control loop measures the difference between the output voltage and a fixed reference voltage and uses that difference to reduce voltage errors. Increasing open-loop gain increases the accuracy of regulation. However, it reduces stability. Stability is defined as the ability of the regulator to prevent oscillations and ringing during step changes.

Capacitive power supply

A capacitive power supply, also known as a capacitive dropper, is a device that converts higher mains AC voltage to a lower DC voltage through the capacitive reactance of a capacitor. This type of power supply has many benefits, and can be used for a variety of different applications.

A typical capacitive power supply circuit includes a first capacitor C with a D.C. output voltage Vout. This voltage is obtained by comparing a voltage Vac applied to the input terminals of the capacitive power supply with the voltage Vout. A resistor R1 is also connected in series with the capacitor C1, with the cathode of the diode D1 connected to terminal one.

Another important feature of a capacitive power supply is its efficiency. Its efficiency is much higher than that of a resistive power supply, and its size and weight are significantly smaller. This makes it a less expensive, smaller solution than a transformer-based power supply.