OR Gates Slash Noise Coupling In Digital Potentiometer Applications

By Michael Gambuzza, February 14, 2011

when you're esigning with a digitl pot, you will want to keep noise from the digital bus off the analog signl. Here's how to do it with or-gates.

Spreadsheet Guides Quest For Stability In Variable-Gain Photodiode Amplifier

By Michael Gambuzza, September 23, 2010

Gyrator Circuit Makes DC Supply Invisible For AC Testing

By Michael Gambuzza, February 12, 2010

This Idea For Design shows how a gyrator circuit can be used to perform certain ac tests on units under test that require a dc-current feed.

Diode Tester Limits Reverse Voltage And Forward Current To Protect Sensitive Junctions

By Michael Gambuzza, December 07, 2009

How to limit forward current and reverse voltage to safe levels while testing diodes.

Detect Loop-Reverse Battery Conditions On A Telephone Line

By Michael Gambuzza, February 18, 2002

Equipment connected to the public switched-telephone network (PSTN) sometimes needs to detect polarity reversals of the battery feed. One common application is the Direct-Inward-Dialing (DID) service that uses what is termed as "loop-reverse battery...

Circuit Provides Ground-Start Supervision For Phone Switching

By Michael Gambuzza, November 20, 2000

Ground start is the primary analog signaling method used between telephone switches such as the central office (CO) and a private branch exchange (PBX). It offers a way to indicate on-hook and off-hook conditions in a voice network. There’s one...