Nuts and Volts - December 2008

TECHFORUM

This is a READER-TO-READER Column.

All questions ANDanswers are submitted by Nuts&Volts readers and are intended to promote the exchange of ideas and provide assistance for solving problems of a technical nature. Questions are subject to editing and will be published on a space available basis if deemed suitable by the publisher. Answers are submitted by readers and NO GUARANTEES WHATSOEVER are made by the publisher. The implementation of any answer printed in this column may require varying degrees of technical experience and should only be attempted by qualified individuals. Always use common sense and good judgement!

All questions and answers should be sent by email to forum@nuts volts.com All diagrams should be computer generated and sent with your submission as an attachment.

QUESTIONS

To be considered, all questions should relate to one or more of the following:

❶ Circuit Design

❷ Electronic Theory

❸ Problem Solving

❹ Other Similar Topics

■ Be brief but include all pertinent information. If no one knows what you're asking, you won't get any response (and we probably won't print it either).

■ Include your Name, Address, Phone Number, and email. Only your Name, City, and State will be published with the question, but we may need to contact you.

■ No questions will be accepted that offer equipment for sale or equipment wanted to buy.

■ Selected questions will be printed one time on a space available basis.

■ Questions are subject to editing.

ANSWERS
■ Include in the subject line of your email,
the question number that appears directly
below the question you are responding to.
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answer is printed. Be sure to include your
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to that effect.
■ Comments regarding answers printed in
this column may be printed in the Reader
Feedback section if space allows.
92 December 2008

>>> QUESTIONS

Solar Battery Charger

I'm looking for a circuit for a micro-controller based solar battery charger that can charge a group of four or eight NiMH rechargeable AA batteries.

#12081 John Weygandt

Belleville, Il

PV vs. EMR

Since solar panels are inherently a diode, would they survive the electromagnetic burst of an EMR weapon?

#12082 Larry Rheaume

Eagar, AZ

SMPS Problem

I recently replaced my SMPS as it was not working. I know the basics about electronics and would like to try to repair it myself (hard disc is not reading). Can someone provide me some information to troubleshoot and repair my unit, if it is possible?

#12083 Karthik

Karnataka

Variable Brightness Of LEDs

I have two sets of LEDs; eight LEDs in each set. The sets need to turn on alternately. However, I would like the brightness to turn on gradually, then fade out. Then, the second would turn on and off in the same manner.

#12084 Arsen Dedic

Palm Springs, CA

Timer Circuit

I am looking for a timer circuit to turn on and provide a source of standard 120 VAC house power for a cycle/duration of 24 hours, once every set number of days (e.g., every 2nd day, or every 3rd day, up to every 12th day). The start and stop times would be at the same hour of day.