## Search found 56 matches

Wed Mar 17, 2010 8:03 am
Forum: General Discussion
Topic: Voltage converter
Replies: 6
Views: 2009

### Re: Voltage converter

The describing equation for the OP's circuit is simply: Vout = 5 - Vin. The Kirchoff's current equation for the inverting node of an inverting amplifier is: I1 = (Vin / Rg) = -I2 = -(Vout / Rf) This assumes a 'virtual ground', or zero volts, at the inverting input, because the non-inverting input is...
Sun May 25, 2008 1:43 pm
Forum: Projects & Kits
Topic: A Simple Superhet by John E. Post, March 2008
Replies: 3
Views: 4254
Thanks, sghioto. I entirely missed that part of the article. Would 30 AWG wire wrap wire be a suitable substitute for magnet wire?
Sat May 24, 2008 7:59 am
Forum: Projects & Kits
Topic: A Simple Superhet by John E. Post, March 2008
Replies: 3
Views: 4254

### A Simple Superhet by John E. Post, March 2008

I do not understand how to connect the antenna (L1) to the SA602's input amplifier. The problem is that the antenna is depicted as a transformer (see schematic below) when in reality it is an inductor. In other words, the antenna is a two-terminal device, not a four-terminal device. http://users.ade...
Tue Sep 25, 2007 6:01 am
Forum: Computer Programming
Topic: Need help on using AVR CodeVision C compiler
Replies: 14
Views: 12695
There is a space between the 'i' and the '++' in the for-loop declaration. Maybe that is giving the compiler fits.
Wed Sep 05, 2007 4:50 pm
Forum: General Discussion
Topic: Technical Dictionary
Replies: 9
Views: 4962
Here is another electronics dictionary
http://www.electronicdefinitions.com/
Fri Nov 24, 2006 4:55 am
Forum: General Discussion
Topic: Any spare gold soldering tip, please ?
Replies: 17
Views: 7290
Antex makes a gold-plated tip. Is this what you are looking for?

http://www.mmnewman.com/shopping/shopex ... 1&catid=20
Wed Nov 08, 2006 4:55 am
Forum: General Discussion
Topic: Optoisolator selection
Replies: 6
Views: 2928
Now that I have received the recommended optos, I have a question about their use. Here is the internal schematic of the part: http://users.adelphia.net/~andrewconklin/FOD050L.png The data sheet says the following: A separate connection for the bias of the photodiode improves the speed by several or...
Tue Oct 31, 2006 6:59 pm
Forum: General Discussion
Topic: MicroChip PIC30F Assembler
Replies: 10
Views: 4833
Point taken. I became too focused on Microchip's tools due to the reference to ASM30 in the original post.
Tue Oct 31, 2006 5:55 am
Forum: General Discussion
Topic: MicroChip PIC30F Assembler
Replies: 10
Views: 4833
Here is an excerpt from a 30F document: Unlike the MPASMâ„¢ assembler (for use with PICmicroÂ® MCUâ€™s), MPLAB ASM30 does not generate error files, hex files, or symbol and debug files. MPLAB ASM30 is capable of creating a listing file and a relocatable object file (that may or may not contain debug...
Tue Oct 31, 2006 5:25 am
Forum: General Discussion
Topic: MicroChip PIC30F Assembler
Replies: 10
Views: 4833
There are two gross over-simplifications in markp's desires. The first is the notion that it is possible to create an executable without a linker. The second is the underestimation of how much more complex the programming specification is for the newer, 16-bit PICs, such as the 30F series. The 16-bi...
Thu Oct 26, 2006 6:51 pm
Forum: General Discussion
Topic: Optoisolator selection
Replies: 6
Views: 2928
Oh, the hardware portion of my programmer is a piece of crap - I would give its schematic away for a nickel. The part that took time was the PC software. It's not great, either. I bit-bang the parallel port as fast as possible using a high speed clock available on the PC. I hope these new optos impr...
Thu Oct 26, 2006 12:14 pm
Forum: General Discussion
Topic: Optoisolator selection
Replies: 6
Views: 2928
Thanks Philba, I put some on order. I learned a hard lesson with this - Mouser carries much more product than they put into their catalog. I could have saved a few dollars on the 33F's by ordering from them rather than MicrochipDirect because the Mouser catalog did not list the 33F series when in fa...
Thu Oct 26, 2006 7:39 am
Forum: General Discussion
Topic: Optoisolator selection
Replies: 6
Views: 2928

### Optoisolator selection

I am a hobbyist embarking on the conversion from the dsPIC30F to the dsPIC33F series, and since the 33F is 3.3V device, I plan to build a new programmer for it. My current home-brewed programmer uses 4N25 optos to isolate the PC's parallel port signals from the target. It is painfully slow. I had to...
Fri Sep 22, 2006 3:52 pm
Forum: General Discussion
Topic: Power Supply 'Hot Swapping'
Replies: 5
Views: 2250
You cannot prevent all accidents from happening. It will require some prudence on the part of the operator. Install an E-stop and LED indicator in series with the DC voltages. We had a similar circumstance in my last job wherein we hot-plugged Molex connectors to our drives and sometimes we would bl...
Fri Sep 22, 2006 3:20 pm
Forum: Computer Programming
Topic: Terribly new question.
Replies: 9
Views: 5903
This chip is an OTP (one time programmable). Go with a different USB chip for your project. The June edition of N&V has an article about creating an USB interface with a Microchip PIC. Investments in programming hardware for PIC's would likely be of more use in future projects.