Search found 341 matches

by Ron H
Mon Jan 13, 2003 7:04 am
Forum: General Discussion
Topic: UAV project
Replies: 7
Views: 3132

Re: UAV project

I suspect Miguel didn't know that UAV means "unmanned aerial vehicle". He probably thought you wanted to apply your idea to a full-sized airplane.<p>Ron
by Ron H
Thu Dec 19, 2002 2:51 pm
Forum: General Discussion
Topic: Poptronics Is Gone???
Replies: 48
Views: 17227

Re: Poptronics Is Gone???

Have you guys looked at this?<p>http://www.poptronics.com/interactive/<p>Ron
by Ron H
Sun Dec 15, 2002 8:39 pm
Forum: General Discussion
Topic: Hollywood tracker beacon?
Replies: 9
Views: 2672

Re: Hollywood tracker beacon?

There is probably already a system that works like this, but I'm not aware of it:<p>If you and your target each have a transmitter and receiver, then you can initiate a pulse, and if the target receives it, it immediately sends one back. Since the propagation velocity of radio waves is known (~3*10^...
by Ron H
Mon Dec 09, 2002 7:39 pm
Forum: General Discussion
Topic: Auto CDI ignition
Replies: 1
Views: 842

Re: Auto CDI ignition

I don't have the article, but you can find schematics on the Internet. Do a Google search for "capacitor discharge ignition schematic". I found these in short order:<p> http://home.labridge.com/~wnoble/WN_articles/CD-ignition-SK.pdf <p> http://control.gsnu.ac.kr/~f007dan/cicuit/page2.htm#cdi.gif <p>...
by Ron H
Fri Dec 06, 2002 6:53 am
Forum: General Discussion
Topic: Waves Converter
Replies: 38
Views: 8368

Re: Waves Converter

Power is measured in dB. Frequency is measured in Hz. They are totally independent. You can't convert one to the other.<p>I'm curious who it is you want to jam. If you own a restaurant or a theater or something similar, I'll be sympathetic. Otherwise... if I knew that you were jamming phones in my n...
by Ron H
Tue Dec 03, 2002 12:30 pm
Forum: General Discussion
Topic: Analog to digital
Replies: 2
Views: 873

Re: Analog to digital

I think I know what you need, but I haven't been able to find a part number. Some FM receivers had (have?) analog tuning and a counter chip that measured the local oscillator frequency, digitally added the IF frequency, and had outputs to drive a digital display. Can any of you other forum trolls co...
by Ron H
Sun Dec 01, 2002 6:58 am
Forum: General Discussion
Topic: Hallicrafters Radio Speaker
Replies: 3
Views: 1346

Re: Hallicrafters Radio Speaker

Here's a manual you can download that might have the answer:<p>ftp://bama.sbc.edu/downloads/hallicra/sx99/<p>Ron
by Ron H
Fri Nov 29, 2002 11:22 am
Forum: General Discussion
Topic: Auto switch from battery to USB power?
Replies: 5
Views: 2523

Re: Auto switch from battery to USB power?

http://www.maxim-ic.com/appnotes.cfm/appnote_number/190<p>I found this by searching Google for "battery switchover".<p>Ron
by Ron H
Fri Nov 29, 2002 7:06 am
Forum: General Discussion
Topic: Current Sensing Schematic
Replies: 9
Views: 1970

Re: Current Sensing Schematic

Edd, I believe a magnetically unbiased (no bias magnet nearby) reed switch is not sensitive to the polarity of the magnetic field.<p>A little research shows that reeds can switch in as little as 0.5 ms, INCLUDING bounce. I found one that was spec'ed at 3 ms.<p>Chris, I can see that, if the AC field ...
by Ron H
Thu Nov 28, 2002 7:21 pm
Forum: General Discussion
Topic: Current Sensing Schematic
Replies: 9
Views: 1970

Re: Current Sensing Schematic

Chris, it seems to me that the alternating magnetic field produced by your coil will cause the reed switch to open and close at a 120 Hz (100 Hz in UK) rate.<p>Ron
by Ron H
Wed Nov 27, 2002 10:52 am
Forum: General Discussion
Topic: Baylis
Replies: 11
Views: 2460

Re: Baylis

Winding up that radio spring is a conversion from chemical energy (the food you consumed) to electrical energy. I wonder how efficiently our bodies process food, and whether our bodily waste (feces, urine, sweat, CO2, etc.) should be considered pollution?<p>Ron
by Ron H
Mon Nov 25, 2002 5:20 pm
Forum: Robotics
Topic: 0 1 to -1 0 1
Replies: 15
Views: 7020

Re: 0 1 to -1 0 1

Hogwash, Harold. 15 is made up of two symbols: 1 and 5. Sure, you can redefine it as one symbol if you want, but you'll wind up having to explain yourself every time you do it - just like you did here.<p>Dean, I used Dogpile as my search engine of choice until I discovered Google. I had never even h...
by Ron H
Mon Nov 25, 2002 12:48 pm
Forum: General Discussion
Topic: Gate inputs.
Replies: 2
Views: 840

Re: Gate inputs.

In the TTL logic families, each input has an internal pullup resistor whose current must be shunted to ground with an impedance that is low enough to bring the input voltage below the logic low threshold. This is an oversimplified explanation, but it is adequate for this discussion. As Harold said, ...
by Ron H
Mon Nov 25, 2002 6:51 am
Forum: General Discussion
Topic: SBS
Replies: 5
Views: 1422

Re: SBS

Take a look at this datasheet:<p>http://www.pwrx.com/pwrx/docs/bso8d.pdf<p>It has a description of the part, an equivalent circuit, and a schematic of a typical application.<p>Search http://www.google.com for "silicon bilateral switch" for more info.<p>Ron
by Ron H
Sun Nov 24, 2002 3:58 pm
Forum: General Discussion
Topic: Power capacitor 1-4 farad for car amplifier
Replies: 20
Views: 5600

Re: Power capacitor 1-4 farad for car amplifier

If the capacitor's initial charge is Vi, and you have a constant load resistance, at time t the voltage V will be<p>V = Vi * e^(-t/(R*C)) where R*C is called the time constant and e = 2.71828 is Napier's constant.<p>For example, if you apply a 10 ohm load to a 1 Farad cap that is initially charged t...