Gennette Bruce says:
Here is a simple idea that works really well to isolate noise generating sections of a circuit from sections that need clean power - it uses just 3 diodes and 1 extra capacitor.
In the common leg of a 3 terminal regulator you add a diode that raises the regulator's output voltage by the drop across the diode. You then fit 2 identical diodes to the output from the regulator to drop the voltage back down to where it would have been. Separate smoothing capacitors are then fitted to the 2 separated outputs.
The really cool thing is that the outputs from the 2 diodes are completely isolated from each other and can be used to power an analog AND a digital circuit from the same regulator.
1N4004 diodes that cost less than 10 cents are rated at 1amp/400volts and 470uF caps are about 60 cents, so you can add this second output to your existing analog power supply for less than a dollar to give you a separate digital power supply.
|file: /Techref/power/isolation.htm, 1KB, , updated: 2007/7/3 11:25, local time: 2017/1/18 02:10,
|©2017 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?|
<A HREF="http://www.piclist.com/techref/power/isolation.htm"> Power Isolation</A>
|Did you find what you needed?|
PICList 2017 contributors:
o List host: MIT, Site host massmind.org, Top posters @20170118 Van Horn, David, RussellMc, David Duffy (AVD), IVP, Justin Richards, Sean Breheny, alan.b.pearce, speff, Brent Brown, Neil,
* Page Editors: James Newton, David Cary, and YOU!
* Roman Black of Black Robotics donates from sales of Linistep stepper controller kits.
* Ashley Roll of Digital Nemesis donates from sales of RCL-1 RS232 to TTL converters.
* Monthly Subscribers: Gregg Rew. on-going support is MOST appreciated!
* Contributors: Richard Seriani, Sr.
Welcome to www.piclist.com!