World's Worst Soldering!

Started by Cursitor Doom in sci.electronics.design1 week ago 53 replies

Hi all, I just fixed up this classic Tek 466 scope I've been meaning to get around to sorting out for the last few years. As you can see, my...

Hi all, I just fixed up this classic Tek 466 scope I've been meaning to get around to sorting out for the last few years. As you can see, my soldering is atrocious. I've been soldering this type of circuitry for 50 years and never got any better at it in all that time. When it comes to soldering and part-placement, I suck donkey dick! Check it out and enjoy at my expense: https://ww...


Need same color bi-directional LED 3mm

Started by Jeff Liebermann in sci.electronics.design2 weeks ago 52 replies

Is there such a thing as a bi-directional LED where each polarity is the same color? I can find plenty of 3mm LED's where each direction is...

Is there such a thing as a bi-directional LED where each polarity is the same color? I can find plenty of 3mm LED's where each direction is a different color (bi-color), such as: but none where both directions


A mechanical neural net

Started by Anonymous in sci.electronics.design2 weeks ago 6 replies

A mechanical neural net https://www.sciencedaily.com/releases/2018/10/181016131940.htm

A mechanical neural net https://www.sciencedaily.com/releases/2018/10/181016131940.htm


"Modern VHF/UHF Front-End Design" (1985)

Started by MikeP in sci.electronics.design2 weeks ago 47 replies

Any opinions on this article? https://archive.org/details/ModernVHFUHFFrontEndDesign I think I basically understand how amplifiers,...

Any opinions on this article? https://archive.org/details/ModernVHFUHFFrontEndDesign I think I basically understand how amplifiers, filters and mixers work, including how intermodulation products arise and how noise gets amplified by subsequent stages; however I've been struggling to get an intuitive grip on things like noise figures and 2nd/3rd order intercept points. I've now scan...


Spad games III

Started by George Herold in sci.electronics.design2 weeks ago 59 replies

So I built (copied) an active quench circuit with capacitive coupling. It follows Mario's first circuit. ...

So I built (copied) an active quench circuit with capacitive coupling. It follows Mario's first circuit. here https://www.dropbox.com/s/2kcxt1j9bbgotql/Mario1.pdf?dl=0 Here's a blow up of fig 2 with some values.. either gleaned from the report or figured out. https://www.dropbox.com/s/91es10mgizgjge8/fig2.JPG?dl=0 A few changes in the circuit. I couldn't find any use for the I_3 res...


Cheap electric start for inverter generator using a BLDC module revisited

Started by Johnny B Good in sci.electronics.design2 weeks ago 2 replies

This is more of a follow up, describing where I got up to in my exploration of the subject matter. As such, it's turned into another epic...

This is more of a follow up, describing where I got up to in my exploration of the subject matter. As such, it's turned into another epic read. Apologies for that but there was rather a lot of detail to cover. Way back in the mists of time (Tue, 17 Jul 2018 18:35:11 +0000 to be precise), I created a thread with the subject : "Electric start for suitcase inverter generator by using its...


Dispersion in Coax

Started by George Herold in sci.electronics.design2 weeks ago 47 replies

Hi All, this is a question from a physics demo group that I'm passing on to you. Here's the question. One of my prof's want to do a...

Hi All, this is a question from a physics demo group that I'm passing on to you. Here's the question. One of my prof's want to do a demo where you input a square wave into a very long coax cable and look at the output of the cable with an oscilloscope to see that the high frequencies are traveling faster than the low frequencies. Anyone in Tapper land do an experim


7812 abuse

Started by Anonymous in sci.electronics.design2 weeks ago 36 replies

I've got a job where life would be so much simpler if I could let an unpowered 7812 see -12v on its output pin. The -12v is from a lead acid, and...

I've got a job where life would be so much simpler if I could let an unpowered 7812 see -12v on its output pin. The -12v is from a lead acid, and yes I know they don't charge at 12v etc etc. I could put up with an occasional failure, but not a lot obviously, it's a low cost consumer app. Has anyone tried this, or have insight into the expectable results? Moving to a much less common


Discreet-component CO detector

Started by Jeff Layman in sci.electronics.design2 weeks ago 4 replies

How many designs today use discreet components rather than LSI and/or SMD? I just had a 6-years old domestic carbon monoxide detector reach its...

How many designs today use discreet components rather than LSI and/or SMD? I just had a 6-years old domestic carbon monoxide detector reach its expiry date, so thought I'd have a look inside. It was made entirely of discreet components - no LSI, and not a single SMD. Photo here: One other odd thing was that the device used red, yellow, and green leds for


Toyota radiators

Started by Anonymous in sci.electronics.design2 weeks ago 20 replies

I think they should recall all those radiators. Http://75.101.56.77/toyota What do you think? How difficult is it to have coolant level...

I think they should recall all those radiators. Http://75.101.56.77/toyota What do you think? How difficult is it to have coolant level sensors? It would catch the problems earlier and avoid engine damages.


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