Does it have to be a BJT? What about a mosfet or a 78xx regulator with a cap on its adjust pin? Ryan On 6/03/2015 4:17 PM, "Bob Blick" wrote: > Hi Ryan, > You are right! It does not increase the storage of the filter capacitor. > If you have an unregulated power supply with a filter capacitor (an > old-school DC wall-wart, for example) there will be ripple under load. > The greater the load, the greater the ripple. What the described circuit > can do (with appropriate transistor/resistor/capacitor choices) is > maintain the output voltage a little under the lowest peak of the > ripple. The ripple on the output is less than, but follows, a multiple > of the circuit's capacitor. The nice thing about it is that the output > voltage drops with load, so it almost tracks the lower ripple peak, > something a 78xx regulator can't do. It also has less insertion loss. > Cheerful regards, Bob > > On Thu, Mar 5, 2015, at 06:50 PM, Ryan O'Connor wrote: > > That page is really informative. However, I'm left wondering about the > > physics. How can a capacitor which stores charge possibly be "multiplie= d" > > without any additional storage? > > > > Ryan > > > > On 6 March 2015 at 02:46, Adam Field wrote: > > > > > On Wed, Mar 4, 2015 at 12:17 PM, Bob Blick wrote: > > > > Hi Joe, > > > > You could use a one transistor pass element to multiply a capacitor= .. > Let > > > > me see if I can find an example on the web... nope. here's napkin > art. > > > > > > > > Bob > > > > > > ESP has a good page on the concept: > > > > > > http://sound.westhost.com/project15.htm > > -- > http://www.fastmail.com - Access all of your messages and folders > wherever you are > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .