## Search found 341 matches

Tue Sep 10, 2002 8:18 am
Forum: General Discussion
Topic: Basic Inductor Question
Replies: 17
Views: 4913

### Re: Basic Inductor Question

I found an excellent discussion on power factor correction at http://www.lmphotonics.com/pwrfact.htm<p>Ron
Mon Sep 09, 2002 1:30 pm
Forum: General Discussion
Topic: Caps
Replies: 21
Views: 5177

### Re: Caps

Billdar said what I was in the process of composing, but I'll throw in my (additional) two cents anyway.<p>Magnetic fields are created by moving charges. If the charges are static, there is no associated electromagnetic (EM) field - only an electrostatic one. Do a Google search for "electrostatic fl...
Mon Sep 09, 2002 7:18 am
Forum: General Discussion
Topic: Thermoelectric (TE) Coolers
Replies: 3
Views: 1035

### Re: Thermoelectric (TE) Coolers

Looking at a datasheet from TI,<p> http://www-s.ti.com/sc/psheets/slos365a/slos365a.pdf <p>there is an equation on page 8 that relates the loss in cooling ability to the ripple current. Higher ripple current yields lower cooling capability. Therefore, you should minimize ripple current (within reaso...
Sat Sep 07, 2002 7:54 pm
Forum: General Discussion
Topic: Caps
Replies: 21
Views: 5177

### Re: Caps

A pretty good explanation can be found at http://biz.howstuffworks.com/capacitor.htm <p>However, when Mr. Brain gets to the discussion of DC blocking (passing AC), he gets it partially wrong:<p>"A capacitor can block DC voltage. If you hook a small capacitor to a battery, then no current will flow b...
Sat Sep 07, 2002 7:24 pm
Forum: General Discussion
Topic: Basic Inductor Question
Replies: 17
Views: 4913

### Re: Basic Inductor Question

Newbie, you are right on. If you charge a perfect capacitor and open circuit it, the voltage will remain the same forever. If you charge a perfect inductor with a current and then short circuit it, the current will flow forever. Remember, the time constant of an RL circuit is L/R. If R is zero, the ...
Fri Sep 06, 2002 2:29 pm
Forum: General Discussion
Topic: EARPHONES
Replies: 14
Views: 3259

### Re: EARPHONES

"But they all oscillate, rotate, or gyrate, even Crystal, Kristal and Chrystal? "<p>As I recall, one of them did osculate. Sorta like oscillate, only different. <p>Ron
Fri Sep 06, 2002 9:22 am
Forum: General Discussion
Topic: EARPHONES
Replies: 14
Views: 3259

### Re: EARPHONES

<snip>And, the "crystal" is a different animal from the "crystal" in "crystal oscillator". There may another Crystal that's different. Ever date her in your youth, Ron?<unsnip><p>I think she spelled it "Kristal". Or was it "Chrystal"?<p>Earphone crystals and (oscillator) quartz crystals are, of cour...
Thu Aug 29, 2002 7:06 am
Forum: General Discussion
Topic: animal tracking transmitter
Replies: 13
Views: 3724

### Re: animal tracking transmitter

Your circuit description is indecipherable. Why don't you post the URL of the schematic?
Wed Aug 28, 2002 1:58 pm
Forum: General Discussion
Topic: EARPHONES
Replies: 14
Views: 3259

### Re: EARPHONES

You can get crystal earplugs for \$2.50 each from http://www.midnightscience.com/ <p>The above URL is the home page for The Xtal Set Society. I purposely left off the address for the catalog, but you can easily find it from the home page.<p>I cut my teeth on crystal radios many years ago, and I still...
Thu Aug 08, 2002 8:18 am
Forum: General Discussion
Topic: 100vdc regulated power supply schematic Need
Replies: 2
Views: 1168

### Re: 100vdc regulated power supply schematic Need

On the outside chance that Edd's solution doesn't meet your needs, you could adapt this design:<p> http://www.glass-ware.com/tubecircuits/High_Voltage_Regulator.html <p>For 100 volts output, change the sum of R2 and R3 from 295k to 95k, and lower the unregulated HV DC supply to around 130 volts.<p>R...
Tue Jul 09, 2002 7:35 am
Forum: Robotics
Topic: A little help with MOSFETs and PIC
Replies: 5
Views: 2999

### Re: A little help with MOSFETs and PIC

You can buy back issues. Go to http://www.nutsvolts.com/backissue.htm<p>Ron H
Wed Jun 19, 2002 10:25 am
Forum: General Discussion
Topic: Cordless phone range
Replies: 16
Views: 4041

### Re: Cordless phone range

Dean wrote:<p>"In Oklahoma City, it averaged to around 13 blocks per mile. Oklahoma City is one of the few cities where danged near every street runs either east-west or north-south, so there're no curves to skew the block count and the entire area is set up with section roads. In Oklahoma, it's lik...
Tue Jun 18, 2002 7:20 am
Forum: General Discussion
Topic: tricky dc voltage problem
Replies: 7
Views: 2114

### Re: tricky dc voltage problem

Go to http://www.poptronics.com/forums/electronic_bench/ and see the post entitled "Invert and Level Shift". A simplified schematic is posted there.<p>Ron H
Thu Jun 13, 2002 7:05 am
Forum: Robotics
Topic: A little help with MOSFETs and PIC
Replies: 5
Views: 2999

### Re: A little help with MOSFETs and PIC

The spec you are looking for is V(BR)DSS. The datasheet says 100 volts, so you should be OK. I haven't seen the article, but I'm assuming the gate is driven by a 5 volt logic level. The IRL540 cannot take more than 10 volts gate-to-source.<p>Ron H
Sun Jun 09, 2002 7:34 pm
Forum: General Discussion
Topic: gfi schematic and circuit explanation
Replies: 2
Views: 1009

### Re: gfi schematic and circuit explanation

Here is a pretty good explanation of GFCI operation:
http://www.codecheck.com/gfci_principal.htm<p>Ron H