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Detecting... load, current... um...

Started by Anonymous in sci.electronics.basics4 hours ago 23 replies

Now sure how to describe the problem in few words, sorry. I have two circuit boards (to be designed), A and B. A has the power supply= . A and...

Now sure how to describe the problem in few words, sorry. I have two circuit boards (to be designed), A and B. A has the power supply= . A and B will be connected by a longish, 2 conductor wire. The wire will b= e used to supply 12V+ and ground from A to B. B has no other source of powe= r. B needs to signal A when something happens. For various reasons, I can't replace the wire with a...


Battery charging question...

Started by Dave in sci.electronics.basics6 hours ago 6 replies

Just a quick question, but aren't we supposed to charge a rechargable battery gy sending current through it in reverse to the normal polarity of...

Just a quick question, but aren't we supposed to charge a rechargable battery gy sending current through it in reverse to the normal polarity of the battery? Just wondering why it doesn't seem to be working... Thanks


One-shot triggered rising and falling?

Started by Douglas Beeson in sci.electronics.basics18 hours ago 9 replies

Hi all, I'm sure someone has an quick answer for this. I'd like a simple circuit or a part that produces a pulse -- basically a one-shot --...

Hi all, I'm sure someone has an quick answer for this. I'd like a simple circuit or a part that produces a pulse -- basically a one-shot -- with both a rising edge and falling edge input signal. All the multivibrator ICs I have seen will trigger on rising OR falling, but not on both. How can I get a trigger on both? Thank you! -- Douglas Beeson


The 2 ways to make mark & space equal on a 555 astable circuit

Started by Adam Funk in sci.electronics.basics20 hours ago 32 replies

From this link & other places, I see there are (at least) 2 ways to make the 555 astable circuit produce a square wave with a 50%...

From this link & other places, I see there are (at least) 2 ways to make the 555 astable circuit produce a square wave with a 50% duty cycle: * putting 2 diodes into the circuit & using the same resistance from Vcc to discharge as from discharge to trigger & threshold, as shown in the "Improved 555 Oscillator Duty Cy


dead unused NiMH AA cells

Started by Adam Funk in sci.electronics.basics2 days ago 6 replies

I recently opened a pack of NiMH AAs that I'd had lying around for a while, & some of them wouldn't charge at all. I tried putting them in the...

I recently opened a pack of NiMH AAs that I'd had lying around for a while, & some of them wouldn't charge at all. I tried putting them in the fancy German charger as well (I can't remember the model name, but it's the one that has discharge, test, & refresh modes) but it just showed "null" for them, as if they weren't even there. Is there some need to charge NiMH cells as soon as you buy ...


What does this circuit do?

Started by Stumpy in sci.electronics.basics2 days ago 21 replies

If anything. http://reliablehomeenergy.net/wp-content/uploads/2015/03/scheme.png They claim that $49 for instructions, $63 for parts get you...

If anything. http://reliablehomeenergy.net/wp-content/uploads/2015/03/scheme.png They claim that $49 for instructions, $63 for parts get you a single home "magnetic energy generator" designed by Tesla. http://reliablehomeenergy.net/tl I assume the video has an AC coil under the table.


Math Problem

Started by Jim Thompson in sci.electronics.basics3 days ago 10 replies

A math problem over my head... Would some math whiz solve this for me? Thanks! ...Jim...

A math problem over my head... Would some math whiz solve this for me? Thanks! ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | m


The Best Name for Signal Recovery Matched Filtering

Started by Bret Cahill in sci.electronics.basics4 days ago 17 replies

I just assumed "matched filtering" included the deconvolution and other steps to recover the original signal's shape. In this case it was...

I just assumed "matched filtering" included the deconvolution and other steps to recover the original signal's shape. In this case it was actually easier to invent a new filter -- I assumed it already existed -- than to be scholarly and do some research. To avoid confusion with the terminology from now on the filter that takes the convolution of a noisy signal like a conventional matche...


RE-Tube amp questions

Started by Anonymous in sci.electronics.basics6 days ago 19 replies

Thanks everyone for your answers. I guess I can see some of the reasons why tube amps tend to be low power. I am going to try Jurb's suggestion...

Thanks everyone for your answers. I guess I can see some of the reasons why tube amps tend to be low power. I am going to try Jurb's suggestion and check out Audiokarma. I have found a battery operated headphone tube amp that uses tiny tubes that also looks interesting. What I need to do is find someone local to me that has a tube amp in the 8 to 16 watt range and listen to it. Then hook my P...


OT: PERL Question

Started by Jim Thompson in sci.electronics.basics2 weeks ago 6 replies

OT: PERL Question How do I search for a range of multi-digit numbers, say find any three digit number between 192 and 222? ...

OT: PERL Question How do I search for a range of multi-digit numbers, say find any three digit number between 192 and 222? ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | ...


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