Question: How do I determine which power supply I need?   Answer: The power supply will be determined on your overall system. The type of hardware being powered and the max voltage will need to be determined. This will let you know how many power supplies are needed and what voltage is needed. There are two types of power supplies. Switching and Linear. Switching – takes the AC input, but rectifies and filters into DC first, and then is converted back to AC at some high switching frequency, steps down the voltage with a transformer, then is rectified and filtered into a DC output. This pertains to the “output” side. The “input” side has two types that are “switchable”. Switching is considered high efficiency and normally cost more. Linear - takes the AC input usually 120VAC or 240VAC, then steps it down the voltage using a transformer, then rectifies and filter the input into a DC output. Linear is considered less efficient. It uses bigger filters and heavier transformers and is less expensive than a Switching unit. There are also other options to choose from such as the number of outputs, relays and if they need a fire trigger. There are online amperage converters to help you determine the requirements for your power supply.     In addition to a broad offering of product and service solutions, IDN offers pre-sale and post-sale technical support. The benefit to you is that We Make Security Simple. Whether your task is related to high-security systems, electronic access control, door installation, or other, our experts are here to assist. Just let us know how we can help. Do you have a question, or need a quote? Contact your local IDN Branch, or ask the Electronic Access Control Ace through our website. © Copyright IDN, Inc.