Search found 93 matches

by ljbeng
Fri Aug 27, 2004 7:49 am
Forum: General Discussion
Topic: Source for 25 Watt Amp
Replies: 5
Views: 1494

Source for 25 Watt Amp

I need to amplify the output of a MP3 player, one channel, to 25 Watts. I need a single chip, 12V supply, readily available. Any suggestions? I have looked at the audio amplifier chips from Phillips. Are these easy to get in small (<25) quantities? Thanks.
by ljbeng
Wed May 19, 2004 6:24 am
Forum: General Discussion
Topic: Mystery Transistor - is Dr. Sherlock Holmes out there?
Replies: 8
Views: 2456

Re: Mystery Transistor - is Dr. Sherlock Holmes out there?

Sherlock Holmes was not a Doctor. His companion was Dr. Watson so maybe that was your confusion. I hope this helps. :)
by ljbeng
Tue May 11, 2004 6:21 am
Forum: General Discussion
Topic: please recommend a microcontroller
Replies: 2
Views: 1061

Re: please recommend a microcontroller

Go with the 18Fxxx part and use the www.ccsinfo.com C compiler. I have converted many of my assembly program to C and have simplified the code considerably.
by ljbeng
Tue Apr 27, 2004 8:01 am
Forum: General Discussion
Topic: 24 VDC to 5 VDC
Replies: 9
Views: 2405

Re: 24 VDC to 5 VDC

Thanks for all the help. It looks like I will have to go the LM2575 route. I plugged one into 24V pulling 200ma and the component barely heats up. I had some inductors custom wound for this once, I will have to do it again. The only inductors I could find from Mouser were physically large and bulky....
by ljbeng
Mon Apr 26, 2004 6:55 pm
Forum: General Discussion
Topic: 24 VDC to 5 VDC
Replies: 9
Views: 2405

24 VDC to 5 VDC

I buy a pc board for my product that uses an LM340T-5 regulator. When powered by 12V (250 ma) it does not heat up too much. My customers want to power the device from 24VDC. The regulator gets super-hot when doing this and I think 24v is a little too high for the specs. I tried an LM2940CT-5.0 (work...
by ljbeng
Tue Mar 16, 2004 6:24 am
Forum: General Discussion
Topic: Sending data on AC supply lines
Replies: 11
Views: 3180

Re: Sending data on AC supply lines

Look at Phillips Semiconductor TDA5051A. It works up to 2400 baud. I have been experimenting with them. Just beware of mistakes in the datasheet. Get ahold of an application engineer.
by ljbeng
Thu Feb 12, 2004 7:06 am
Forum: General Discussion
Topic: Build an MP3 player?
Replies: 4
Views: 1384

Re: Build an MP3 player?

http://www.walrus.com/~raphael/html/mp3.html
$123 kit
or<p>www.tetraphon.com
$150 done<p>Circuit cellar had an article about interfacing a pic to a compact flash. Then you will need an MP3 decoder data sheet.<p>www.vlsi.fi/datasheets/vs1001.pdf
by ljbeng
Wed Feb 04, 2004 1:18 pm
Forum: General Discussion
Topic: Computer as Guitar Amp
Replies: 3
Views: 1023

Computer as Guitar Amp

Just because I have never tried this, just curious if anyone else has. Can an electric guitar be plugged into the line-in or mic-in of a computer sound card and get any decent sound levels? Thanks.
by ljbeng
Mon Nov 24, 2003 6:40 am
Forum: General Discussion
Topic: how to ? schematic to pc board
Replies: 17
Views: 4439

Re: how to ? schematic to pc board

N9AOK,<p>Draw your schematic and save. Now start the pcb lay out software. Now choose the File menu and choose "Link Schematic to PCB...." Now you have to have a pcb component for every component on the schematic. The software will flag you if something is missing.
by ljbeng
Thu Nov 20, 2003 2:29 pm
Forum: General Discussion
Topic: how to ? schematic to pc board
Replies: 17
Views: 4439

Re: how to ? schematic to pc board

www.expresspcb.com<p>Free schematic and board layout. Link schematic to board.
by ljbeng
Thu Oct 09, 2003 7:03 am
Forum: General Discussion
Topic: Reverse Polarity Catch 22
Replies: 3
Views: 1433

Reverse Polarity Catch 22

I have a device (Unit A) that will require DC power 10 to 24v DC in. The power must be supplied by the installer. Unit A will be connected through a serial port to another device (Unit B). Unit B has it's own power source. It is powered by AC lines and creates it's own internal DC power.<p>I want to...
by ljbeng
Thu Aug 21, 2003 2:45 pm
Forum: General Discussion
Topic: Diode Voltage multipliers
Replies: 10
Views: 3791

Re: Diode Voltage multipliers

Let me ask:<p>What is the 120vac device? Is it something that is creating dc itself? If so, can the battery directly power the circuitry?
by ljbeng
Fri Aug 15, 2003 6:14 am
Forum: General Discussion
Topic: help wanted - motor control device
Replies: 1
Views: 1548

Re: help wanted - motor control device

Send me a message at [email protected]<p>Do you want microprocessor control? I don't usually use discrete logic. Thanks.
by ljbeng
Thu Jul 24, 2003 8:21 am
Forum: General Discussion
Topic: Bike spedometer
Replies: 10
Views: 2657

Re: Bike spedometer

LM2907<p>ICL7137<p>
You will need a frequency to voltage converter and an analog to digital converter with display driver.<p>[ July 24, 2003: Message edited by: ljbeng ]<p>[ July 24, 2003: Message edited by: ljbeng ]</p>
by ljbeng
Thu Jul 17, 2003 2:21 pm
Forum: General Discussion
Topic: Project
Replies: 6
Views: 2780

Re: Project

Send me the details please. I have done a number of temperature related projects using PIC microprocessors. Thanks.<p>[email protected]