On Sun, 11 Feb 2024 10:32:32 -0800, John Larkin <jl@997PotHill.com>
wrote:

>On Sun, 11 Feb 2024 17:40:10 +0000, Cursitor Doom <cd@notformail.com>
>wrote:
>
>>On Sun, 11 Feb 2024 07:28:39 -0800, John Larkin <jl@997PotHill.com>
>>wrote:
>>
>>>On Sun, 11 Feb 2024 10:39:49 +0100, Jeroen Belleman
>>><jeroen@nospam.please> wrote:
>>>
>>>>On 2/11/24 02:22, John Larkin wrote:
>>>>> On Sat, 10 Feb 2024 22:33:15 +0100, Jeroen Belleman
>>>>> <jeroen@nospam.please> wrote:
>>>>>
>>>>>> On 2/10/24 18:27, Don wrote:
>>>>>>> Jeroen Belleman wrote:
>>>>>>>> Don wrote:
>>>>>>>>> Jan Panteltje wrote:
>>>>>>>>>> John Larkin wrote:
>>>>>>>>>>> Cursitor Doom wrote:
>>>>>>>>>>>> John Larkin wrote:
>>>>>>>>>>>>> Fred Bloggs wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>>> This is the new circuit analysis: exploring operation in Spice and looking at graphs.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> https://www.elektormagazine.com/articles/circuit-analysis-with-ltspice-12v-lamp-flasher
>>>>>>>>>>>>>
>>>>>>>>>>>>> Too much talking for too little circuit.
>>>>>>>>>>>>
>>>>>>>>>>>> Mr. Bloggs had to use LTspice for a 12V lamp flasher?? Jeez!
>>>>>>>>>>>
>>>>>>>>>>> Using Spice is reasonable, easier than computing exponentials by hand.
>>>>>>>>>>> I use Spice for voltage dividers, filters, rectifiers, RLC delays, all
>>>>>>>>>>> sorts of stuff.
>>>>>>>>>>
>>>>>>>>>> I mostly use pepper, Chili and salt as spices, some sugar etc.
>>>>>>>>>> If this spice stuff continues people will need it before throwing a ball...
>>>>>>>>>> Why not just ask AI to design the circuit for you,?
>>>>>>>>>>
>>>>>>>>>> And no guarantee that anything in LTspice works -in- or even resembles reality!
>>>>>>>>>>
>>>>>>>>>> Real hands on testing is needed to get a clue.
>>>>>>>>>
>>>>>>>>> Tis true the Spice won't help you
>>>>>>>>> With a simple radio set:
>>>>>>>>>
>>>>>>>>> <https://crcomp.net/crystalrx/a.png>
>>>>>>>>> [...]
>>>>>>>>
>>>>>>>> Why not?
>>>>>>>
>>>>>>> Good question. And, with all due respect, you ought to post some Spice to
>>>>>>> show me how you do it.
>>>>>>>
>>>>>>> Danke,
>>>>>>>
>>>>>>
>>>>>> Something akin to this.
>>>>>>
>>>>>> Jeroen Belleman
>>>>>>
>>>>>> ================================================
>>>>>> Version 4
>>>>>> SHEET 1 880 680
>>>>>> WIRE -144 96 -176 96
>>>>>> WIRE -32 96 -64 96
>>>>>> WIRE 272 96 176 96
>>>>>> WIRE 352 96 272 96
>>>>>> WIRE 464 96 416 96
>>>>>> WIRE 512 96 464 96
>>>>>> WIRE 544 96 512 96
>>>>>> WIRE -176 128 -176 96
>>>>>> WIRE -32 128 -32 96
>>>>>> WIRE 176 128 176 96
>>>>>> WIRE 272 128 272 96
>>>>>> WIRE 464 128 464 96
>>>>>> WIRE 544 144 544 96
>>>>>> WIRE -176 240 -176 208
>>>>>> WIRE -32 240 -32 208
>>>>>> WIRE 176 240 176 208
>>>>>> WIRE 272 240 272 192
>>>>>> WIRE 464 240 464 208
>>>>>> WIRE 544 240 544 208
>>>>>> FLAG 176 240 0
>>>>>> FLAG 272 240 0
>>>>>> FLAG 464 240 0
>>>>>> FLAG 544 240 0
>>>>>> FLAG -32 240 0
>>>>>> FLAG -176 240 0
>>>>>> FLAG 512 96 out
>>>>>> SYMBOL ind2 160 112 R0
>>>>>> SYMATTR InstName L1
>>>>>> SYMATTR Value 16µ
>>>>>> SYMATTR Type ind
>>>>>> SYMBOL cap 256 128 R0
>>>>>> SYMATTR InstName C1
>>>>>> SYMATTR Value 6.28n
>>>>>> SYMBOL diode 352 112 R270
>>>>>> WINDOW 0 32 32 VTop 2
>>>>>> WINDOW 3 0 32 VBottom 2
>>>>>> SYMATTR InstName D1
>>>>>> SYMATTR Value AA112
>>>>>> SYMBOL res 448 112 R0
>>>>>> SYMATTR InstName R1
>>>>>> SYMATTR Value 1meg
>>>>>> SYMBOL cap 528 144 R0
>>>>>> SYMATTR InstName C2
>>>>>> SYMATTR Value 10n
>>>>>> SYMBOL ind2 -48 112 R0
>>>>>> SYMATTR InstName L2
>>>>>> SYMATTR Value 16µ
>>>>>> SYMATTR Type ind
>>>>>> SYMBOL bv -176 112 R0
>>>>>> WINDOW 3 -186 181 Left 2
>>>>>> SYMATTR InstName B1
>>>>>> SYMATTR Value V=10k*(1+sin(time*1k*2*pi))*sin(time*1meg*2*pi)
>>>>>> SYMBOL res -48 80 R90
>>>>>> WINDOW 0 0 56 VBottom 2
>>>>>> WINDOW 3 32 56 VTop 2
>>>>>> SYMATTR InstName R2
>>>>>> SYMATTR Value 1
>>>>>> TEXT 72 0 Left 2 !.tran 5m
>>>>>> TEXT 0 112 Left 2 !K12 L1 L2 1u
>>>>>> TEXT -152 0 Left 2 ;Transmitter
>>>>>> TEXT 264 0 Left 2 ;Crystal set receiver
>>>>>
>>>>> Suggestions:
>>>>>
>>>>> Reduce the modulation a bit. It distorts at 100%.
>>>>>
>>>>> Make R1 2K, like an old dynamic headphone.
>>>>>
>>>>> Change the coupling to 50u. A good antenna makes a lot of signal.
>>>>>
>>>>> You can use a BAT54 schottky.
>>>>>
>>>>
>>>>
>>>>You don't expect high fidelity from a crystal set, but OK, fair enough.
>>>>C2 was meant to model a piezo earbud. I should actually measure one...
>>>>
>>>>I got the values of C! and L1 wrong. C1=300pF is more reasonable,
>>>>and then L1=84.43uH. In practice, of course, C1 would be tuned and L1
>>>>would be fixed at 80uH or so, but either way works.
>>>>
>>>>The voltage of B1 and the tranformer coupling factor are just guesses,
>>>>based on the knwoledge that crystal sets actually do work.
>>>>
>>>>Jeroen Belleman
>>>
>>>I think that most xtal sets do some sort of impedance matching from
>>>the antenna up into the main coil, taps on the coil or an extra
>>>winding. A really longwire antanna will have a lot of capacitance and
>>>an equivalent lowish impedance.
>>>
>>>The people who have made xtal sets over the last century or so don't
>>>seem to have been very quantitative.
>>>
>>>I've wondered if I can slurp enought power out of the air to light an
>>>LED. My office is in a wooden building about 3 miles from Sutro Tower.
>>>Castro valley is a bowl that I suspect focusses the RF onto us.
>>
>>LEDs require relatively large amounts of current, so I don't see how
>>that would be possible, John. There's only *one* bloke I can think of
>>who could conceivably pull that off and he's long dead, sadly.
>>Edison's nemesis:
>>
>>https://en.wikipedia.org/wiki/Nikola_Tesla
>
>A good LED is visible in typical room light at 1 uA, which would be
>about 2 uW. I'd imagine that a modest antenna and a decent detector
>could do much better than that.
>
>The difference between a crystal set and lighting an LED is that the
>LED case should use the entire spectrum, AM TV FM, which is densely
>packed where I am. That would take some thinking.
>

Neon or similar would be far more easily achievable I reckon.