Search found 82 matches

by jimmy101
Sat Feb 13, 2010 10:25 am
Forum: General Discussion
Topic: LED as power on indicator with AC Mains Supply
Replies: 34
Views: 5963

Re: LED as power on indicator with AC Mains Supply

jwax said: jimmy101- I disagree about using the RMS value. The LED will indeed see the peak voltage. And yes, I neglected to consider the reverse voltage breakdown of the LED, sometimes rated around 5 volts. That being said, I connected a LED with a 56K resistor, applied 240 VAC, 60 Hz, and the LED ...
by jimmy101
Fri Feb 12, 2010 9:35 am
Forum: General Discussion
Topic: LED as power on indicator with AC Mains Supply
Replies: 34
Views: 5963

Re: LED as power on indicator with AC Mains Supply

I think Jwax's calc is off a bit. Assuming an LED in series with a single resistor, the duty cycle is 50% and you use the RMS voltage not the peak voltage. Dropping the current back to 20mA to ensure the LED has a long life; So, 230V/20mA = 11.5K (I ignored the insignificant voltage drop across the ...
by jimmy101
Mon Jan 18, 2010 8:56 am
Forum: General Discussion
Topic: What Should I Do With This Microwave Oven?
Replies: 21
Views: 4028

Re: What Should I Do With This Microwave Oven?

Like others have said, the most likely problem is a bad solder joint. Either on the PCB or internal to the piezo where the wires connect to the substrate. Other than the internal solder joints, Piezo are pretty robust little devices. You should be able to replace the piezo and I would expect that ju...
by jimmy101
Mon Jan 18, 2010 8:43 am
Forum: General Discussion
Topic: Oreck Vacuum Cleaner
Replies: 11
Views: 2598

Re: Oreck Vacuum Cleaner

I think it's a waste of money. Besides if Orek says it "will destroy many viruses, bacteria, mold, and dust mite eggs" then they really don't know what they are talking about and/or they have stretched the truth to the point that they are basically lying. Heck "many" may not even be significant. Bac...
by jimmy101
Fri Jan 15, 2010 10:45 am
Forum: General Discussion
Topic: Circuit for one input - multiple outputs
Replies: 10
Views: 2195

Re: Circuit for one input - multiple outputs

To get the circuit to turn off the output once the input signal goes off you could use a set of AND gates that takes the input signal and one of the output lines and ANDs them together. The output of the AND gate would go the the resistor and then to the power transister etc. You would need to find ...
by jimmy101
Mon Jan 11, 2010 10:43 pm
Forum: General Discussion
Topic: Help to build a Ion Detector, please....
Replies: 7
Views: 3504

Re: Help to build a Ion Detector, please....

To reverse the polarity of the detector couldn't you just ground the antenna and make the old ground conection the new antenna? Would that would flip the detector from a negative ion to postive ion detector? What is the detector going to be used for? Detect the negative ions from an air cleaner type...
by jimmy101
Thu Jan 07, 2010 7:39 am
Forum: General Discussion
Topic: Dew Zapper and PWM DC Motor Controller
Replies: 10
Views: 2286

Re: Dew Zapper and PWM DC Motor Controller

Looking at dyarker's numbers, it looks like you could just use a total length of about 10 to 15 feet of the heater wire. If that is too long for what you thought you needed then just double or triple the amount of heater wire at each location. Or, just hang the excess someplace, like on a chair to k...
by jimmy101
Thu Jan 07, 2010 7:16 am
Forum: General Discussion
Topic: Fios and Molex Connectors
Replies: 5
Views: 1223

Re: Fios and Molex Connectors

You know it's funny too because when i pull out the battery connector it takes almost no force at all. That tells me there are lots of air spaces between the male and female contacts that shouldnt be there. Sounds like it is time to bend a couple of pins. That'll give decent force between the pins ...
by jimmy101
Wed Jan 06, 2010 9:55 am
Forum: General Discussion
Topic: 97' chevy s-10 tach hack question
Replies: 7
Views: 1347

Re: 97' chevy s-10 tach hack question

You could just print new numbers on stickers and stick'm on the face of the gauge. :grin:

Or, if the face of the gage can be removed then scan it and make a duplicate with the proper numbers using an Inkjet printer.
by jimmy101
Wed Jan 06, 2010 9:51 am
Forum: General Discussion
Topic: Dew Zapper and PWM DC Motor Controller
Replies: 10
Views: 2286

Re: Dew Zapper and PWM DC Motor Controller

I think this is a case where KISS applies. You really don't require any type of controller like PWM or PID. It's just a heater after all that doesn't really need precise temperature control. Besides, as soon as you add temp control the complexity of the circuit goes way up. If the original heater se...
by jimmy101
Wed Dec 30, 2009 12:15 pm
Forum: General Discussion
Topic: slot car track
Replies: 20
Views: 3502

Re: slot car track

A D cell will source a fair amount of current, perhaps 20A or more. If the track is burning through the batteries pretty quick then it's likely that track is pulling more than the 600mA the wall wart can supply. Hook an amp meter in series with the track and see how much current it is drawing. You n...
by jimmy101
Fri Dec 04, 2009 4:45 pm
Forum: General Discussion
Topic: Digital to Analog
Replies: 8
Views: 1602

Re: Digital to Analog

Can you find a junked 02? Perhaps it's as easy as removing the speedo from the dash of the 02 and installing in the dash of the 98?
by jimmy101
Mon Nov 30, 2009 11:39 am
Forum: General Discussion
Topic: The Origin of Life (Electrical)
Replies: 35
Views: 7640

Re: The Origin of Life (Electrical)

Very few scientific theories are "proven". In general, it really doesn't matter if a theory (postulate, law, wild ass guess) is proven or not. It only matters that it is useful . The fundamental, inalterable difference between science and "creationism" is that creationism, being a repackaged form of...
by jimmy101
Wed Nov 25, 2009 8:08 am
Forum: General Discussion
Topic: The Origin of Life (Electrical)
Replies: 35
Views: 7640

Re: The Origin of Life (Electrical)

Even if someday someone creates a mathematical model (and physical experiment) of how entropy can be used to create self replicating systems or increasing complexity (Life) Why the focus on entropy? Mentioning entropy without enthalpy is like talking about voltage without current. One is nonsensica...
by jimmy101
Tue Nov 24, 2009 10:06 am
Forum: General Discussion
Topic: SatNav precision, accuracy or resolution...
Replies: 8
Views: 1668

Re: SatNav precision, accuracy or resolution...

In addition to the "intrinsic" accuracy of a GPS receiver you can often increase the practical accuracy beyond the intrinsic accuracy. And, you can increase the precision even farther than the accuracy. Back when civilian systems were limited to ~10m resolution it was possible to get down to a resol...