Power supply for household appliances: types and features, how to choose

Power supply is a device that converts the energy of the electrical grid into a voltage suitable for powering household appliances and devices. If it breaks down, it can be replaced. You only need to know the power consumption characteristics of the equipment and the performance of the power supply.

A power supply has these key characteristics:

• Output and input voltage.
• Output current.
• Power in watts or V/A.

Types of power supplies and their features

Power supplies come in two types depending on their location:

• Built-in or internal power supplies are installed in the system units of computers, in the cases of refrigerators, washing machines. From them comes a wire, which is enough to plug into a socket.
• External power supplies are separate modules in their own case. They are connected to the equipment and to the mains and are used for small-sized equipment: laptops, LCD monitors, etc.

Power supplies differ in their functionality:

• The voltage stabilization option provides a constant voltage that goes to the appliance. If the value of the input voltage is greater than the limit or the connected appliances require more voltage than the power supply can deliver, it will shut down in an emergency or may break down.
• The current stabilization option converts the voltage so that the current remains constant as the power consumption changes. These power supplies are designed for equipment that needs a stable current.
• Power supplies with voltage and current stabilization make the voltage remain constant as the power consumption increases. The current rises to a predetermined level and is delivered to the connected equipment.
• In unstabilized power supplies, the output voltage depends on the input voltage. It is used for equipment that does not require output voltage.

Power supplies differ in the way they work:

• In linear power supplies, the main elements are: a transformer that converts the voltage to a lower voltage, a filter that does not allow voltage spikes.
• Pulsed or inverter power supplies make direct current from alternating current, form pulses of high frequency and feed them to the transformer, rectifier and filter. The units convert it to direct current when they receive it. Pulse models are half the size of linear power supplies and cost more.

How to choose a power supply

Before you buy a new power supply, you need to study the key characteristics on the device or information from the data sheet. Pay attention to such data:

• The power consumption of the equipment (denoted by the numerical values in Volts, V or V) - the same output power should be the power supply.
• The power supply voltage (denoted by a number).
• Input voltage is standard - 220-240 V.
• The current consumption of the equipment - measured in Amperes (A). On the power supply may be indicated as: «OUTPUT CURRENT 1 A», the equipment to which the power supply will be connected - «INPUT CURRENT 1 A». If this information is not specified, the power consumption in watts is used: the number of watts should be divided by the voltage in volts (the power consumption of the equipment or the output power of the power supply) and you get the figure in amperes.
• You need to check what kind of connector the power supply should have - two-pronged, round, USB, etc. It is better to take an old external power supply with you to the store, or take a picture of the plug if you need an internal power supply. When buying the unit online, you can consult a salesperson.

Some models are available in a waterproof case of IP67 class. The letter Y (from 0 to 9) indicates the level of protection against water, Z (from 0 to 6) indicates the degree of protection against ingress of solid particles inside the housing.