Search found 341 matches

by Ron H
Thu Dec 23, 2004 10:34 am
Forum: General Discussion
Topic: Electromagnetic physics question
Replies: 41
Views: 7990

Re: Electromagnetic physics question

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by jwax: steven, apples and oranges. The DC system was designed for DC. Had it been designed and built for AC, the insulation would have been appropriate for AC, and efficiency is not involved. On the...
by Ron H
Wed Dec 15, 2004 6:42 am
Forum: General Discussion
Topic: need transistor help...
Replies: 15
Views: 3117

Re: need transistor help...

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by dacflyer: david >>>i have the base connected to a 10k resistor connected to the output of a 4017 emitter to the led.other lead of led to gnd. and the base to B+ 12v i belive thats right..i am here ...
by Ron H
Fri Dec 03, 2004 2:51 pm
Forum: General Discussion
Topic: passive integrator design
Replies: 4
Views: 1299

Re: passive integrator design

Let's call the first Resistor R1, the first capacitor C1, etc. BTW, you can get the same amount of filtering, but faster settling, by making R2=100k and C2=10nF.<p>For the analysis, assume that you have very low ripple on C1 and C2. For analyzing the voltage on C1, we can then say that no current fl...
by Ron H
Mon Nov 29, 2004 10:29 am
Forum: General Discussion
Topic: Universal Shift Register 74LS194
Replies: 2
Views: 835

Re: Universal Shift Register 74LS194

The 74194 maximum clock frequency is a minimum of 25MHz (read the datasheet again). It will run at any arbitrarily low frequency. You should be able to use it to accomplish what you want.
by Ron H
Sat Oct 16, 2004 8:09 pm
Forum: General Discussion
Topic: Current source
Replies: 64
Views: 16158

Re: Current source

Yeah, I think we pretty much beat this to death. I am posting the circuit I said I had that uses a diff amp of a different sort, along with waveforms. Note that the uotput is inverted relative to the input. http://s02.imagehost.org/0525/0-2_amp_waves.GIF http://s02.imagehost.org/0525/0-2_amp_current...
by Ron H
Sat Oct 16, 2004 6:24 am
Forum: General Discussion
Topic: Current source
Replies: 64
Views: 16158

Re: Current source

Fred, I agree with all that. I just don't understand completely what Yigiter is trying to do (and I'm not sure he does). In this thread, I was guessing that he was trying to charge a car battery, and he wanted to use the car GND as GND for his controller (not to imply that he couldn't use +12V inste...
by Ron H
Thu Oct 14, 2004 1:29 pm
Forum: General Discussion
Topic: Current source
Replies: 64
Views: 16158

Re: Current source

Fred, I could sim that, and I'm sure it will look fine, but here's a quote from Yigiter: <blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>i think i can not do this. because my grounded load is a "car battery" so i can't connect the positive side of my load to 0V.(12V...
by Ron H
Wed Oct 13, 2004 12:00 pm
Forum: General Discussion
Topic: Current source
Replies: 64
Views: 16158

Re: Current source

Fred, can you post a complete schematic? I tried to duplicate your schematic, and I still get an oscillator, but not with the characteristics you mentioned. I'm not too surprised, because the oscillation frequency will wind up being a function of The Ft of the transistors, the beta of the transistor...
by Ron H
Tue Oct 12, 2004 12:33 pm
Forum: General Discussion
Topic: Current source
Replies: 64
Views: 16158

Re: Current source

If you wind up with a lemon, make lemonade. :) <p>A cursory look at MJ2955 vs MJE2955 datasheets looks like the differences are in package and power dissipation.
by Ron H
Tue Oct 12, 2004 8:51 am
Forum: General Discussion
Topic: PET DOOR auto-gatekeeper
Replies: 15
Views: 3619

Re: PET DOOR auto-gatekeeper

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Dean Huster: If the cat's obviously old enough to go out on dates by him/herself, why the importance of the curfew? Or is it a weather thing?<p>Dean <hr></blockquote> He'll want the cat to stay out...
by Ron H
Tue Oct 12, 2004 6:24 am
Forum: General Discussion
Topic: Current source
Replies: 64
Views: 16158

Re: Current source

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by windmiller: RonH:<p>Thanks for your fascinating reply suggesting a comparison of an actual circuit build performance against a circuit simulation performance.<p>I am setup to build and test a 0-2A ...
by Ron H
Mon Oct 11, 2004 6:56 am
Forum: General Discussion
Topic: Current source
Replies: 64
Views: 16158

Re: Current source

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by windmiller: RonH:<p>Congratulations! You are my first literary critic as an electronics writer wannabee.<p>I've built a number of circuits like this and haven't smoked one yet. It's a smoothie.<p>I...
by Ron H
Fri Oct 08, 2004 1:46 pm
Forum: General Discussion
Topic: Current source
Replies: 64
Views: 16158

Re: Current source

I don't like to be critical, but I also hate to see a guy burn up his parts. There are several problems there:<p>1. The loop gain is way too high (with no compensation), which will cause the circuit to oscillate. 2. There is no current limiting through Q1 and Q2.<p>I can post a circuit that uses a h...
by Ron H
Fri Oct 08, 2004 7:26 am
Forum: General Discussion
Topic: Current source
Replies: 64
Views: 16158

Re: Current source

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by windmiller:
RonH:<p>NICE drawing!<hr></blockquote>
Thanks! Linear Technology's <p>SwitcherCAD III.
by Ron H
Thu Oct 07, 2004 10:19 am
Forum: General Discussion
Topic: Current source
Replies: 64
Views: 16158

Re: Current source

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by yigiter: RonH: i want to control that current with a micrprocessor controlled DAC. i will use a voltage divider to divide voltage and a comparator to compare it with my referance voltages. so i can...