2-terminal negative resistance circuits

Would that be an example of negative resistance?

In fact, i have seen a 2-terminal hockey-puck ?regulator? made that way. Excellent high power beastie.

No "Z" types?

Half-baked opinions are not too tasty....

The I/V plot looks like a "Z". For a real example, take any greater-than 7V zener or any silicon PNP or NPN low signal transistor EB junction; run curve from zero to 10mA and you are bound to see the resulting trash. Some are very noisy.

Thanks.

Yes, it is not linear, but nowhere near negative resistance. Do a Spice and you will see how lame it is in action.

It's easy to avoid having silly ideas: never have ideas.

--

John Larkin   Highland Technology, Inc   trk 

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

Zeners will oscillate in an RC circuit at low current. It is very noisy.

--

John Larkin   Highland Technology, Inc   trk 

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

Sorry, do not see it. How about a SPICE to show it?

Thanks.

But if the sun has a BIG corona fart, the whole electrical system in the world goes POP and you will need those pencils (and paper). Real time solid-state graphics..

'Envious and resentful' pretty much covers it.

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Yessir, Tony Williams and I covered that here in depth, about 25 years ago, lots of 500MHZ scope measurements and drawings. Many physics papers from early 60s, but w/o high-speed scopes. Unfortunately the files are somehow missing from my computer.

--
 Thanks, 
    - Win

That sums up "leftism" pretty well.

On a sunny day (Fri, 5 Jul 2019 13:07:24 -0800) it happened Robert Baer wrote in :

Thank you for pointing out my error. I did try it in Ltspice, and indeed you are 100% right. Tried to fix it by changing some component values and even using a zener, but no success. Your incredible wizdom rules again. My hat off! Wonder if I had too much sun or too little 'tronics last week, could well be, big festivities going on here all day.

Could also be some basic units changed over time due to dark matter and dark force.

I also had the idea to do it with a PIC and one transistor, I am sure that will work, but slow. ADC -> software -> DAC -> tranny to short the supply. :-)

Also easy with two BJTs ...

Version 4 SHEET 1 880 680 WIRE -128 -112 -368 -112 WIRE 48 -112 -128 -112 WIRE 176 -112 48 -112 WIRE -368 -48 -368 -112 WIRE 48 0 48 -112 WIRE 176 0 176 -112 WIRE -128 64 -128 -112 WIRE 176 112 176 80 WIRE 176 112 -64 112 WIRE -368 144 -368 32 WIRE 176 160 176 112 WIRE -128 208 -128 160 WIRE -64 208 -128 208 WIRE 48 208 48 80 WIRE 48 208 16 208 WIRE 112 208 48 208 WIRE -128 240 -128 208 WIRE -368 352 -368 224 WIRE -128 352 -128 320 WIRE -128 352 -368 352 WIRE 176 352 176 256 WIRE 176 352 -128 352 WIRE -368 384 -368 352 FLAG -368 384 0 SYMBOL voltage -368 128 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V1 SYMATTR Value PULSE(0 20 0 1m) SYMBOL npn 112 160 R0 SYMATTR InstName Q2 SYMATTR Value 2N3904 SYMBOL npn -64 64 M0 SYMATTR InstName Q4 SYMATTR Value 2N3904 SYMBOL res 160 -16 R0 SYMATTR InstName R2 SYMATTR Value 300k SYMBOL res 32 -16 R0 SYMATTR InstName R6 SYMATTR Value 300k SYMBOL res -144 224 R0 SYMATTR InstName R7 SYMATTR Value 200 SYMBOL res 32 192 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R8 SYMATTR Value 10k SYMBOL res -384 -64 R0 SYMATTR InstName R1 SYMATTR Value 1 TEXT -272 416 Left 2 !.tran 1m

piglet

More fun stuff ...

piglet

On a sunny day (Sat, 6 Jul 2019 15:39:16 +0100) it happened piglet wrote in :

OK, as the voltage rises Q2 starts conducting and switches the load formed by Q1 off. ?

Excellent!

Very well done write-up.