115/230 VAC POWER

Products can be designed to work on 115V primary power or 230V. They can be made to work on either with a jumper or switch to change the transformer primary from 115V to 230V.

Universal power supplies can be supplied that will work on any voltage between 85VAC to 240VAC as well as 115VDC to 330VDC. They are more costly than conventional supplies.

Products that consume very little power can sometimes be powered from the 115/230VAC mains without using a transformer. These supplies are quite inexpensive. Power requirements and human safety are the limitations on using this type power.

LOW VOLTAGE AC POWER

If a low voltage AC supply, such as a control transformer, is available in the overall system, a product can be designed to use the low voltage for power, thus saving another power transformer. This style power supply can quite often also be supplied from a low voltage DC supply as well. It also lends itself well to having a battery backup against loss of the low voltage AC power source.

DC VOLTAGE POWER

If low voltage DC is available in the system, it can possibly be used to power a product directly, thus saving several components in a power supply.

DC inverters can be used to transform an existing DC supply to the required operating voltages for a product. However, inverters add cost to a power supply.

DC inverters can be supplied so a product can be powered from almost any reasonable DC source such as batteries, solar cells, PLC power supplies, or computer power supplies.

Products can also be designed using batteries as their primary power source. Disposable or rechargeable battery supplies can be provided.

POWER SUPPLY DECISION

If a specific supply is not dictated by the product, and more than one primary power source is available, the power source should be chosen based on the most cost effective product design. It is important for the designer to know all the available choices.