Go Back   Home > Forums > Blogs > RJM Audio Blog

If I put my notes here, I might be able to find them again later!
Rate this Entry

Voltage Regulators for Line Level Audio. Part II : The Pass Transistor

Posted 16th January 2014 at 05:14 AM by rjm
Updated 20th January 2014 at 11:21 PM by rjm

Part 2 of a series.

Instead of pulling the output current through R1, we add an npn pass transistor, Q1. The output current now "passes" through the transistor, while the Zener diode still regulates the output voltage by being connected to the transistor base.

The output impedance falls to a few ohms, but the ripple rejection improves only slightly.

This is a useful basic circuit block for audio, but the ripple rejection can easily improved by the addition of a couple of additional components, as we'll see shortly.
Attached Thumbnails
Click image for larger version

Name:	voltageregulator2.png
Views:	464
Size:	90.6 KB
ID:	1217   Click image for larger version

Name:	voltageregulator2b.png
Views:	560
Size:	92.7 KB
ID:	1218  
Attached Files
File Type: asc voltageregulator2.asc (1.2 KB, 197 views)
Total Comments 0



New To Site? Need Help?
Copyright 1999-2017 diyAudio