Power Supply | Electronic Project Circuits

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78xx Power Supply

Of all the voltage regulator ICs, the 78xx family is by far the most established. Not surprisingly! It is difficult to get performance this good with so few outside components necessary.

Just like the famous LM317, the 78xx family incorporates automatic shutdown in case of overheating. You can get up to 1.5A of current with a suitable heat sink. No fuse is required.

Read More source: http://www.geocities.com/tomzi.geo/78xx/78xx.htm
Thank you.

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Categories: Power supply Tags: 78xx, dc voltage regulator, power supply

We are now in a position to learn a practical way of implementing current sources. The circuit schematic below (which has been entered into the pSpice circuit simulator) shows a simple way of doing this using a JFET (see Lecture Notes page 86). Note that the symbol used for the JFET, type 2N3819, is not quite the same as the more widely accepted one we have encountered!

The negative terminal of the supply V1 (battery symbol) is connected to Ground, also known as Node 0, and represents the reference point for any measurements we might make. Although the battery voltage is indicated as 5V, pSpice will let us vary this experimentally over any required range. The current developed by the circuit flows in the drain circuit, and is in fact ID. For this application a light-emitting diode LED is shown as the load, in which the constant current flows. This is a very typical usage for this kind of circuit; the LED works most consistently (giving a steady light output) if the current passing through it can be maintained constant, even if the supply voltage changes – for example, as the battery discharges.

Bread Board Power Supply by LM317

uCHobbyâ€™s first electronics kit is a handy breadboard power supply. The power supply design is simple but just what I needed for my electronics projects. I have seen several similar power supply boards but none had all the features I wanted. This design was also a good first project to help me learn about Kicad.
Source:http://www.uchobby.com/index.php/2008/02/19/bread-board-power-supply/#more-104