[fun] Weird electronic circuits collection

Maybe the memory core logic in the British Elliott 803 computer of yesteryear is then a bit more weird. It is possible to use memory cores a logic elements. The fan-in and fanout are pretty modest: around 3. The logic needs a three-phase non-overlapping clock to keep the data flowing in the intended direction.

--

-TV

I thought they did actually receive the local oscillator leakage - but maybe this stopped being effective when receivers got better shielded.

John

I have heard a variety of explanations for what they might or might not do. I suppose things like detecting the weak leakage signals could be possible. But there is no way they could drive along the road and pin-point which flat in a block of flats is watching TV - and it is in the denser and cheaper housing areas where you would get the highest rates of non-payment. So the real effect of the vans is psychological, to make people think they can't get away with cheating.

Here in Germany it is even more rude. Each and every household pays, whether there is a TV or not. And if you have a home office, it is fairly easy to be counted twice.

The non-private state owned TV system is badly needed as a benefice for retired polititians with certain, eh, merits. They must make sure that is is independent, after all.

\Gerhard

Most (all?) logic input protection diodes are actually BJTs between substrate and VDD.

Pulling an input below VSS causes the majority* of that current to flow into VDD, not VSS!

*The input pin is the emitter, substrate base, and VDD collector. Alpha is small (alpha is emitter current gain), so a lot does still go into VSS (base current).

VDD diodes don't have significant hFE, except maybe in a low-leakage application where you're hammering on some pins. Typically, hFE is 0 between gates, and ~0.03 between inputs of a single gate (for multiple-input types).

On that note, most modern logic latches up over 100mA. Latchup current is limited by internal resistance, usually not much more than I_H. I measured

170mA on an 'HC.

Tim

-- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website:

They didn't have the right inspecteur.

--
Regards, Joerg 

http://www.analogconsultants.com/

From the bygone era:

Vacuum tube inverted operation. Use grid as plate, and plate as grid. Dissipation is way lower, and mu_inv = 1/mu (which consequently means Rp is extremely low, making this semi-popular for direct drive tube amps).

The balance of currents in tetrodes and pentodes. Namely: as plate voltage drops (into the [voltage] saturation region), screen current shoots up. (Cathode current remains ~constant, and the screen-plate system acts like a long tailed pair upon that current.) Or if you vary Vg3, you can cut off the plate, diverting current to the screen. Thus, dual-control pentodes can be used as single balanced mixers (g1 = tail current, g3 = diff pair voltage, g2 and a = output currents).

This leads to certain negative-resistance properties with a single tube:

Tetrodes: secondary emission results in a negative resistance region in the normal plate curves. Mostly undesired and optimized out of newer types (beam tetrodes), but old types (like the #24) had a strong effect.

Secondary emission was also harnessed in some types, e.g. EFP60. Of course, that's not a bug, it's a feature.

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
Website: https://www.seventransistorlabs.com/ 

"Piotr Wyderski"  wrote in message  
news:p0bv3s$ds6$1@node1.news.atman.pl... 
> Hello, 
> 
> just out of curiosity, could youl please name the weirdest 
> practical components abuses/entering the non-linear region/ 
> unusual, non-obvious, but still legitimate applications you know of? 
> I think it is fun to learn about them, here is my list: 
> 
> 1. Saturable reactors and all that spawns from them. 
> 2. Parametric resonance-based magnetic digital circuits. (google =>  
> parametron) 
> 3. Negistor oscillator. 
> 4. Single-transistor photovoltaic (rly?) negative voltage generator. 
> 5. Transformerless valve audio amplifiers. 
> 6. Dynatron oscillator. 
> 7. Voltage regulator valves used as Geiger counters. 
> 
> Best regards, Piotr 
> 
> 
>

How about the cat detector vans of the Ministry of Housinge?

"Housinge?" "It was spelled like that on the van. I'm very observant."

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
https://hobbs-eo.com

We're not taxed on that one either.

There are 42-45 minutes of show for every hour broadcast, just as there always has been. They do stack it up at the end but that's marketing. Yes, that's how you use a FF button (surprised that you had to be told but I guess all technology passes you by).

But you get to pay tax *AND* watch commercials. Fun! There are no recaps after commercials. You're lying.

Not in the sense that "you're the product" on the Internet. Your viewing tastes aren't sold (individually), as they are anytime you browse the Internet.

Yes, apparently snowflakes are drawn to socialism. like moths to fire.

They didn't _have_ to be rusty- you had to put the point of the safety pin right at the edge of the lettering. Gillette blue blades were good. My first radio, from a Radio Craft magazine.

those programs are in contrast to reality, where attention is liable to not be paid when warranted.

NT

Indeed, when new. When in dead VCRs, nukes etc all VFDs are free.

Someone made a dual audio triode using VDF technology, it makes no sense.

NT

Not sure which alternate reality that's from

I'm not understanding this one. Can somebody provide me with a hint?

His cop pal said out loud that Father Brown was the angel of death. And everywhere that Lord Peter went, even on his own honeymoon, bodies appeared.

Absurd plots. There is something to be said for straightforward Philip Marlowe brutality.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

some variation of this

Why does the left side show an asymptote?

Normally, C levels out to ~nominal at 0V, and usually rises slightly in the first few volts.

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
Website: https://www.seventransistorlabs.com/

Here's an over-the-top version, to make a super-precise current amp to drive an NMR gradient coil.

This is a "perfect class B" circuit, effectively class B with zero crossover error.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com