Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
have a scavenge around your friends or neighbours they are bound to have and old computer. The computer has a power supply inside that can supply 5 and 12 volt rails at very high currents.
then all i need is a few different regulators to supply 9v and 6v
what current rated ones should i use?
(as you said they can supply very large currents!)
Kane, It depends on your requirements. You may either use fixed or variable voltage type, 3 terminal regulators.Example,if you use a fixed regulator such as 7809, the out put current is limited to 1amp.On the other hand, a variable voltage regulator such as LM338K, you will be able to get voltages down from 1.2 to 32v max depending on you input voltage with a maximum current of 5amp. The LM 396K with voltages from 1.2 to 15v and a current of 10amp max. In high current applications it is essential to provide adequate heat sinking. Failure to observe this precaution may result in premature current limiting or output voltage foldback due to thermal shutdown.
You can get a .1A regulator in much smaller packages. For example you could find a .1A reg in a TO-92 (or tiny SOT-23) package instead of the larger TO-220 for a 1A.
For a hobbiest there really is no reason to use a smaller current rating.
Another important thing to keep in mind when selecting a regualtor is the power dissipation. If you want a 3.3V supply regulated from a 12V supply at 1 Amp that is (12V-3.3V)*1A = 8.7W which is quite a bit of power to disipate in your regulator. 8.7W will reqire a fair sized heat sink on a TO-220 package or better. So don't just trust the current rating.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.