Search found 11 matches

by UhClem
Sat Feb 06, 2016 8:46 am
Forum: Nuts & Volts Magazine Discussions
Topic: Feb 2016: Why you need an analog front end and how to set...
Replies: 1
Views: 1520

Re: Feb 2016: Why you need an analog front end and how to se

It is best if the opamp has a supply voltage no higher than that of the ADC input it is driving. If the opamp was running from a 5V supply while the ADC was running on 3.3V, the ADC inputs could latch up if the opamp output went above its 3.3V supply. The AD623 is overkill here. It is wildly more ex...
by UhClem
Sun Jun 21, 2015 11:54 am
Forum: General Discussion
Topic: TC wire question..
Replies: 22
Views: 4182

Re: TC wire question..

Looking at the web page for the gauge manufacturer, it appears that the device is designed assuming a constant cold junction temperature of 24C. Variations from that result in errors. So you do not need to use TC extension wire unless the temperature at the connection to the TC wire is at a location...
by UhClem
Mon Mar 03, 2014 3:03 pm
Forum: Nuts & Volts Magazine Discussions
Topic: Solar Charge Controller
Replies: 3
Views: 6853

Solar Charge Controller

In reading this article I noticed an error in the discussion about reverse power flows: "FETs will also conduct both ways, thus creating a potential that the batteries could discharge through the solar panel. To prevent this, an algorithm is used, and when the solar voltage drops below the battery v...
by UhClem
Sat Feb 15, 2014 2:23 pm
Forum: Nuts & Volts Magazine Discussions
Topic: Improved Efficiency 13.8V Power Supply
Replies: 17
Views: 9926

Re: Improved Efficiency 13.8V Power Supply

Name calling yet. I hadn't added a signature to this site because I post so rarely but I thought that anyone could find my contact information from my web page.That could be found using the "Home" llnk. But just so you can call me something besides "troll", I added it. Happy now? That transistor wil...
by UhClem
Fri Feb 14, 2014 6:10 pm
Forum: Nuts & Volts Magazine Discussions
Topic: Improved Efficiency 13.8V Power Supply
Replies: 17
Views: 9926

Re: Improved Efficiency 13.8V Power Supply

The closed loop output impedance is a good guide to the possible peak current in a short circuit case. Other values such as Rds and capacitor ESR are specified as maximum values whereas the worst case for a short is minimum value. You cannot assume that the Rds will be at its MAX limit to protect t...
by UhClem
Wed Feb 12, 2014 5:04 pm
Forum: Nuts & Volts Magazine Discussions
Topic: Improved Efficiency 13.8V Power Supply
Replies: 17
Views: 9926

Re: Improved Efficiency 13.8V Power Supply

Let me see if I have this right. In order to prove to you that Kirchhoff's voltage law is correct I have to build a high current power supply that I don't need. No thanks. I don't understand why you think that the closed loop output impedance of the power supply applies in a short circuit condition....
by UhClem
Tue Feb 11, 2014 6:23 pm
Forum: Nuts & Volts Magazine Discussions
Topic: Improved Efficiency 13.8V Power Supply
Replies: 17
Views: 9926

Re: Improved Efficiency 13.8V Power Supply

1. I did see your load test and an output impedance of 8 milliohms is mediocre. The output is going to drop about twice the IR loss in the wire from the filter capacitor to the output terminal. I could explain in great detail but you don't want a long discussion. The 80mV drop in your load test coul...
by UhClem
Mon Feb 10, 2014 6:22 pm
Forum: Nuts & Volts Magazine Discussions
Topic: Improved Efficiency 13.8V Power Supply
Replies: 17
Views: 9926

Re: Improved Efficiency 13.8V Power Supply

Hi Dave, Thanks for reading my article. As you say you have made numerous comments, I'll try to address some of them here. Thanks for the response. Feedback is always good. Firstly your minor nit about the regulator ground connection. The 723 does not sense the negative voltage from pin 4, it sense...
by UhClem
Sat Feb 08, 2014 4:59 am
Forum: Nuts & Volts Magazine Discussions
Topic: Improved Efficiency 13.8V Power Supply
Replies: 17
Views: 9926

Improved Efficiency 13.8V Power Supply

This article got me thinking but my comments grew too long for a reasonable post here. So I whipped this up.
by UhClem
Sun Sep 01, 2013 7:33 am
Forum: Nuts & Volts Magazine Discussions
Topic: Build A Headset Amplifier, Sept 2013
Replies: 6
Views: 3942

Re: Build A Headset Amplifier, Sept 2013

Q11 is operated as a current source.

In other words, this is a Class A amplifier. If I was going to go Class A for a headphone amplifier I would probably base it on something from the Nelson Pass DIY site. Like: http://headwize.com/?page_id=105
by UhClem
Mon Jan 07, 2013 4:49 pm
Forum: Nuts & Volts Magazine Discussions
Topic: January 2013 Gravimeter
Replies: 4
Views: 3876

Re: January 2013 Gravimeter

It really doesn't matter because it is a horrible sensor and even if it wasn't the system cannot measure at the resolution required. In spite of what the article claims the variation of gravity at any fixed location will be no more than about 300 microgals. (1 gal = 1 cm/sec/sec). So the plot showin...