HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Comment
Jon Titus
User Rank
Blogger
Re: Part V: Tricks With PIC: Using the Trusty PIC Microcontroller
Jon Titus   1/20/2012 5:36:05 PM
NO RATINGS
Q: What would be your recommendation for measuring Battery voltage thru a micro A/D, say a 9-volt battery?  Simply using a voltage divider causes current draw while the micro is shut down.

 

A:  Yes, if you use two resistors to create a voltage divider you continue to draw current all the time.  Use a small NPN transistor between the resistors and ground and turn it on with an output pin at logic 0.  Then current will flow through the resistors and you can measure the voltage.  Just account for the voltage drop across the NPN transistor when you calculate the resistor values needed to get a voltage you can measure.



Partner Zone
Latest Analysis
The new draw-it-on-a-napkin is the CAD program. As CAD programs become more ubiquitous and easier to use, they have replaced 2D sketching for early concepting.
These free camps are designed for children ages 10 to 18. Attendees are introduced to 3D CAD software and shown how 3D printers can make their work a reality. Here we check out the stops in California and Utah.
A University of Chicago graduate has invented a compact elliptical trainer that lets people work out at their desk while they work.
Dean Kamen told an audience at MD&M East 2014 that FDA regulators aren't to blame for stalling innovation in the medical device industry. Hear what he had to say.
Battery maker LG Chem Power Inc. plans to offer a new cell chemistry that could serve as the foundation for an affordable electric car with a 200-mile driving range by 2017.
More:Blogs|News
Design News Webinar Series
7/23/2014 11:00 a.m. California / 2:00 p.m. New York
7/17/2014 11:00 a.m. California / 2:00 p.m. New York
6/25/2014 11:00 a.m. California / 2:00 p.m. New York
5/13/2014 10:00 a.m. California / 1:00 p.m. New York / 6:00 p.m. London
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Aug 4 - 8, Introduction to Linux Device Drivers
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: August 12 - 14
Sponsored by igus
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service