John Allain wrote: Much better to use one of the circuits that come with most data sheets that show how to increase power output using additional components (power transistors).

It's not generally a good idea to run regulators in parallel to increase the current rating, unless they're designed for this. If they are, then the data sheet will indicate this (and will probably give an example circuit). However, (a) 3-terminal 5V 5A regualtors exist and (b) the data sheet of many 3 terminal regulators shows how to increase the current capability using external transistors. That siad, remember that linear regulators are very inefficient (power equal to the load current mulitiplied by the different between the input and output voltages goes out as heat), and that you might be better considering a swtiching regulator for such currents. -tony

At 08:44 PM 5/17/03 -0400, you wrote: The 7905s are minus 5 V regulators. It uses - voltage input (say -12VDC) on the first pin, return for both the input V and output V on the second pin and outputs a regulated minus 5VDC output on the third pin. IF your power input is floating (no common ground) you can use a 7805 (+5 VDC) rgulator to do the same thing. Connect -Vin to pin 2, +Vin to pin 1, +Vout to pin 3 and -Vin to pin 2. The important thing to remember with this circuit is that the input and out sides do not have a common ground. That's not a problenm in some applications but it is in others. that I get came w/o datasheets. You hardly need a data sheet for a 78xx or 79xx. They're extremely easy to use. Once you'd used them once you should need to look a a data sheet again. Joe