Surge Protectors (SP) and Uninterruptable Power Supplies (UPS): Their Differences; and What Protection to Expect From Each of Them. by Myron N. Daniels This article is primarily concerned with our C64/128 computers and connected peripherals, such as drives. printer, modem, and etc. This article is also applicable to other computers and related equipment. Only quality surge protector (SP) and uninterruptible power supply (UPS) units are considered in this article. Too many units on the market claim to be what the name implies; however, they're not very good at really doing it. Price should not be the factor used to determine the quality of either unit. We usually say, "You only get what you pay for." The basic differences between the units are: 1. An SP is a portable protective device that plugs into an electrical receptacle in your home or office. Then, you plug equipment to be protected into one of the several outlets provided, including a modem's telephone line. The SP protects your computer from an electrical power surge containing spikes of higher than normal line voltage. Commonly referred to as Transient Voltage Spikes, they last about 1 to 2 millionths of a second and can be as great as 5,000 to 6,000 volts. The SP clamps the spikes down to a non-destructive value. Think of a power surge like when a dam breaks. A sudden rush of water surges down a normally running stream. Think of spikes as big rocks, having a shape of upside down garden carrots. being pushed along at great speed & force. When a power surge hits the input of the SP, the components inside it are designed to CLAMP DOWN and suppress that surge and spike. If a surge is too great, an internal fusible link will melt, opening the electric circuit to the SP, and power to the connected devices will stop immediately. AN SP should be considered an expendable sacrificial device. Its only purpose is to save your equipment from catastrophic destruction. If it lasts past one hit, that's gravy! The cost of the SP to that of the protected equipment is considered negligible. The SP must then be returned to the manufacturer for repair. It has done it's job. In the event that a surge is too great, and your equipment does get damaged from a power surge & spike, the manufacturer of a quality SP will replace your damaged equipment, up to the value of your losses. This guaranty will be stated someplace on the box, SP, or on a separate document. Important, keep that sales receipt; you will need it should you ever have a need to file a claim. A high quality SP having good quality internal components. will also have a couple of indicating lights on it indicating its operational status as having electrical power to it and, is in normal, protective, working order My SP is made by American Power Conversion (APC), model NET71, $43 plus shipping and handling. APC provides up to $25,000 lifetime warranty with this SP, should it fail to protect the equipment connected to it. About the UPS unit. First, the UPS unit is not considered an expendable sacrificial device. The internal battery & unit is intended to be continuously usable for many years One very good reason for having a UPS unit: When you experience a power outage for whatever the reason, the computer and peripherals shut down. You've lost your work. You sit there crying with frustration, uttering many nasty words to yourself. Oh yes, you're grateful that the SP has saved the equipment from possible damage, but you had a deadline to meet, or to go fishing. Salvation cometh via the UPS. It continues to provide electrical power to the computer an devices plugged into it, allowing you to save your work and shut down safely. Whew! On loss of normal power, the battery in it automatically powers up a built in inverter. The inverter converts battery DC power to a simulated AC current. Some quality units even have a limited SP circuit built in. Why I bought both units: two incidents caused me to become a believer. 1. A contractor digging a trench for a waterline severed an underground power line, causing an electrical outage. I lost some data but the spike in the surge cost me a Star XB 2425 color printer-- $449 plus shipping and handling. 2. Shortly after incident #1, we had a heavy windstorm in the Koolau mountains. High voltage power lines touched and knocked out the electric power to the area where I live. All lights went out, and my C-128 computer shut down. All data not saved was lost. That did it! Never again was I going to be a victim of an electrical power outage! As club members know, my home is on the windward side of Oahu, in Haiku Village in a valley. We have, and still do experience frequent long lasting power outages. Until the two experiences noted above, I had lucked out with only loss of data and time. My UPS unit is an APC mode, Back UPS Pro-650. Its capacity is 650 volt amps (VA); cost $289 plus shipping and handling. I'm very happy now. (From Hawaii On-Line, July-August 1997, via the Commodore Information Center, http://home.att.net/~rmestel/commodore.html)