Search found 40 matches

by EPA III
Fri Nov 21, 2014 12:11 pm
Forum: General Discussion
Topic: HD44780 Based LED Display: Scrolling Text False Start
Replies: 0
Views: 2826

HD44780 Based LED Display: Scrolling Text False Start

I have been experimenting with scrolling text on some HD44780 based LED displays of various sizes. The commands I talk about below are those for that device, not any particular PIC code. I first clear the display and home the cursor sending a 01 command to the display. Then I change to One Line mode...
by EPA III
Sat May 10, 2014 8:15 pm
Forum: Nuts & Volts Magazine Discussions
Topic: Zeener Diodes in Parallel: 72 Watt Power Supply, May 2014
Replies: 2
Views: 3645

Zeener Diodes in Parallel: 72 Watt Power Supply, May 2014

The schematic for the module used in this project, Figure 4, shows D2 and D3 as two 2.5V zeener diodes that are connected in parallel. They are in series with a 2.2K resistor for a fairly standard arrangement to provide a reference Voltage for the Voltage comparators a bit further in the circuit. I ...
by EPA III
Wed Aug 28, 2013 3:59 pm
Forum: Nuts & Volts Magazine Discussions
Topic: Build A Headset Amplifier, Sept 2013
Replies: 6
Views: 3608

Build A Headset Amplifier, Sept 2013

While reading this article I noticed in the schematic that one of the output transistors, Q11 apparently does not have any connection to the signal on it's base. Instead, it appears to be biased at about a fixed -10 Volts via a 2.2K resistor and an LED. Is this correct? If so, can the author or some...
by EPA III
Sat Feb 16, 2013 5:04 pm
Forum: General Discussion
Topic: Desoldering Temperature
Replies: 6
Views: 1154

Re: Desoldering Temperature

Generally soldering and un soldering operations require about the same temperature and in theory that depends on the type of solder being used. Every shop I have worked in with a variable temperature soldering station invariably always had the temperature control crank all the way up, no matter what...
by EPA III
Sat Feb 16, 2013 4:43 pm
Forum: General Discussion
Topic: Would you have this cutters for sale ?
Replies: 8
Views: 1629

Re: Would you have this cutters for sale ?

I cannot envision ANY flush cutter being rated for piano wire. ...<snip>.... Can you say tungsten carbide? Even though tungsten carbide should be OK for hardened wire, I have had carbide diagonal cutters but was never brave enough to use them for piano wire. Soft steel wire perhaps, but not piano w...
by EPA III
Sun Jun 10, 2012 12:00 am
Forum: General Discussion
Topic: True impedance for TV tuners input ?
Replies: 12
Views: 2025

Re: True impedance for TV tuners input ?

The 75 Ohm figure is probably due to the characteristics of available coaxial cable and the need to transfer as much POWER from the antenna to the tuner as possible to keep the noise in the system down. Also at RF frequencies, most antennae are going to have an impedance that is in the range of, per...
by EPA III
Sat Jun 09, 2012 11:40 pm
Forum: General Discussion
Topic: FCC Certification
Replies: 8
Views: 2102

Re: FCC Certification

You are probably in more danger from other elements of the circuit. Logic devices and switching power supplies can often radiate a lot of RF noise. A good Faraday cage will help a lot.
by EPA III
Sat Jun 09, 2012 11:36 pm
Forum: General Discussion
Topic: AC Plugs!
Replies: 21
Views: 3544

Re: AC Plugs!

The three prong plug, with a safety ground was introduced for safety as others have said. I can recall some lamps and other devices of the 50s and perhaps earlier that were a real safety hazard with their two prong, un-polarized plugs. In my teenage years I repaired many such devices that scared the...
by EPA III
Sat Jun 09, 2012 3:42 pm
Forum: General Discussion
Topic: Magnet in conductive media...
Replies: 21
Views: 4374

Re: Magnet in conductive media...

The simple answer to your question is yes. When a conductor is placed in a magnetic field and there is relative movement, a potential or EMF (Voltage) will be generated. If there is a path to support it, current will flow. Now, exactly what will happen in a real world situation is more complex becau...
by EPA III
Sat Jun 09, 2012 3:03 pm
Forum: General Discussion
Topic: Question About IR Reciever, re: PICAXE PRIMER June 2012
Replies: 2
Views: 846

Re: Question About IR Reciever, re: PICAXE PRIMER June 2012

Steve,

I have not posted a lot on this forum so I am not familiar with the common usage of the various boards. Some forums have most activity on the general board(s). So, thanks for the suggestion. I have done so.
by EPA III
Sun Jun 03, 2012 6:44 pm
Forum: General Discussion
Topic: Question About IR Reciever, re: PICAXE PRIMER June 2012
Replies: 2
Views: 846

Question About IR Reciever, re: PICAXE PRIMER June 2012

In reading the referenced article in the June 2012 issue of Nuts&Volts, I was particularly interested in the discussion on the recommended IR receiver in the first two paragraphs. I am working on a device that uses such a receiver and I want one that would work with as many existing TV/VTR/BluRay/et...
by EPA III
Fri Apr 06, 2012 11:18 pm
Forum: Job Board
Topic: Are you a Subscriber? Why, or why not?
Replies: 34
Views: 159741

Re: Are you a Subscriber? Why, or why not?

I subscribe to Nuts & Volts, both print and digital versions. I started some years ago as an advertiser with a very small ad when the magazine was new. I dropped it after a year or two but picked up a print subscription several years ago. I signed up for the digital version recently so I could have ...
by EPA III
Sun Jan 01, 2012 11:58 pm
Forum: General Discussion
Topic: Solar Cell Powered Battery Charger for Indoor Use
Replies: 4
Views: 999

Solar Cell Powered Battery Charger for Indoor Use

I would like to have a charging device to keep a battery pack in the 5-12 Volt range charged in an indoor location. The batteries would probably be AA size and would be called upon to power a receiver and control circuit 24/7 and a servo motor for irregular periods averaging about 2 minutes per hour...
by EPA III
Fri May 01, 2009 12:02 am
Forum: General Discussion
Topic: Diamond coated cutters/bits cutting steel
Replies: 18
Views: 2262

Re: Diamond coated cutters/bits cutting steel

Diamond wheels are not the first choice for sharpening steel tools or cutting steel parts because diamond is carbon and will be absorbed by the steel. The diamond wheels cost a lot more than a similar sized non-diamond wheel and most prefer to reserve the diamond wheels for things like tungsten carb...
by EPA III
Thu Apr 30, 2009 11:48 pm
Forum: General Discussion
Topic: Need Schematic for Tektronix 432 Scope
Replies: 5
Views: 920

Re: Need Schematic for Tektronix 432 Scope

Robert, Much thanks for the web site. Great resource. I am having a bit of trouble downloading the manual, but at least they do have it. Thanks again, Have you tried BAMA (Boat Anchors Manual Assn.) yet? Just google up BAMA on search engine and they list many older quality instrument manuals for fre...