Search found 1549 matches

by dyarker
Fri Nov 30, 2018 12:53 pm
Forum: General Discussion
Topic: need help to find blue led bulb
Replies: 17
Views: 1917

Re: need help to find blue led bulb

You did not look at the page at the link Dacflyer gave. The calculations were for a bulb like that, not a single indicator LED. An LED is a diode, but the PIV is like 5V. For use in a 120VAC circuit another diode (or bridge) with a PIV of at least 200V is needed. With all components in the bulb, The...
by dyarker
Fri Nov 30, 2018 7:53 am
Forum: General Discussion
Topic: need help to find blue led bulb
Replies: 17
Views: 1917

Re: need help to find blue led bulb

I never said your dual contact socket had power on the shell. I was answering Externet who said a bayonet would expose 120VAC. Even if shell were used, properly connected it would be safe. Repeat, I DID NOT (NOT) say your setup used the shell for power. From the page you linked, it seems it contains...
by dyarker
Fri Nov 30, 2018 4:32 am
Forum: General Discussion
Topic: need help to find blue led bulb
Replies: 17
Views: 1917

Re: need help to find blue led bulb

A dropping resistor for 120VAC would be a huge beast. A dropping capacitor wastes a LOT less power.

And because it is for AC a rectifier is also needed.

Cheers,
by dyarker
Thu Nov 29, 2018 1:28 pm
Forum: General Discussion
Topic: need help to find blue led bulb
Replies: 17
Views: 1917

Re: need help to find blue led bulb

Dacflyer, Then how would the shell get 120VAC on it like Externet suggested. In vehicles dual contact bulbs are sometimes used for brake and turn signal. The bulbs have two elements, one contact to each ans the shell is common return. So not using shell at all for electrical contact doubles the no p...
by dyarker
Tue Nov 27, 2018 5:54 pm
Forum: General Discussion
Topic: need help to find blue led bulb
Replies: 17
Views: 1917

Re: need help to find blue led bulb

I believe they are not made/marketed because when inserting/replacing such bayonet bulb, the outer case terminal is exposing 120VAC to fingers.
???Neutral to shell, switched hot to contact.
by dyarker
Tue Nov 27, 2018 12:59 pm
Forum: General Discussion
Topic: need help to find blue led bulb
Replies: 17
Views: 1917

Re: need help to find blue led bulb

... makes them look very faded. Because they are! A white "LED" is really a blue LED with fluorescent elements. Some blue light causes some green fluorescence. Some blue light causes some red fluorescence. Some blue light leaks out. The combination makes white. A blue filter absorbs 2/3s of the lig...
by dyarker
Wed Nov 21, 2018 4:53 am
Forum: General Discussion
Topic: Edenpure Classic space heater...NOT LEVEL
Replies: 17
Views: 5426

Re: Edenpure Classic space heater...NOT LEVEL

Copper is also more expensive.

People that don't know/care about a fairly small difference in performance and appearance go for the cheaper. so that is what mostly made. Others buy more expensive thinds for long term cost efficiency or "status".
by dyarker
Tue Nov 20, 2018 4:12 am
Forum: General Discussion
Topic: How to select the Gate Drive Resistor
Replies: 4
Views: 703

Re: How to select the Gate Drive Resistor

Like I said before for the power filter capacitor, doing the math will pick the components.

See if you can find a copy of Fundamentals of Electronic Devices by Ronald J. Tocci.

I am not reference material for a paper.

Turn cell phone off in class.

Cheers,
by dyarker
Mon Nov 19, 2018 2:47 pm
Forum: General Discussion
Topic: Edenpure Classic space heater...NOT LEVEL
Replies: 17
Views: 5426

Re: Edenpure Classic space heater...NOT LEVEL

not sure what the advantage is.
copper is a better heat conductor
by dyarker
Fri Nov 16, 2018 12:08 pm
Forum: General Discussion
Topic: Forum Update! Secure!
Replies: 16
Views: 2375

Re: Forum Update! Secure!

((even the spammers were encrypted while created user accounts :grin: , (different protection called for)))
by dyarker
Fri Nov 16, 2018 4:16 am
Forum: General Discussion
Topic: How to select the Gate Drive Resistor
Replies: 4
Views: 703

Re: How to select the Gate Drive Resistor

What is your major?
by dyarker
Thu Nov 08, 2018 12:33 pm
Forum: General Discussion
Topic: Microphone in a bubble...
Replies: 7
Views: 1078

Re: Microphone in a bubble...

Oh yeah! How waterproof? Rain/spit/sweat? Or, submerged? (and depth?)
by dyarker
Wed Nov 07, 2018 3:12 pm
Forum: General Discussion
Topic: Microphone in a bubble...
Replies: 7
Views: 1078

Re: Microphone in a bubble...

Not a truely rigid bubble. Sound (higher and lower preasure) on the outside needs to deform/flex to make higher and lower presure in the air inside.

Same for "Gummy Bear" soft, except sound is absorbed, nothing inside to vibrate the mic element.
by dyarker
Wed Nov 07, 2018 7:09 am
Forum: General Discussion
Topic: How select the Commonly Used Electronic Components
Replies: 5
Views: 951

Re: How select the Commonly Used Electronic Components

The pick of a part usually narrows down to one or two when you "do the numbers". Following your power supply cap example - You need the minimum voltage the load can run with, and maximum current it will draw. The peak of the maximum rectified voltage minus then minimum the load can use is the supply...
by dyarker
Mon Nov 05, 2018 10:57 am
Forum: General Discussion
Topic: Lithium Ion charger hack..
Replies: 7
Views: 1109

Re: Lithium Ion charger hack..

Wiper of a pot to IC temperature measuring pin. Ends of pot to Vcc and common. Adjust pot till IC cuts the charging current. Measure voltage at wiper. Warm NTC to temperature where cell charging should stop. Measure resistance of NTC. A touch of algebra (or longer way with Ohm's Law) gives resistanc...