low voltage to drive LED flash (not successful in simulation, but in breadboard successful)

[ankyxia06]

I firstly did in breadboard with this circuit except I orginally used light-sensative resistor, which is around 1kohm at daytime and above 160kohm in darkness. it oscillates with LED as capacitor adds up to power source to offer higher voltage than what needs to kick LED red on.

In MS since there is no light-sensative resistance so the light-sensative resistor was changed to 300k variable resistance, and firstly it is dragged to 0-5% then click simulate so as to have capacitor charged to around 1.5v then increase variable resistance to 80%-100% so to kick Q1 out of off-state status. But it did not oscillate. 

pasted this MS file for reference. 

[tipa]

"In MS since there is no light-sensative resistance so the light-sensative resistor"-can be made from a voltage-controlled resistor, and the voltage can be represented as a luminous flux
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Here's what happened to me...

 

[ankyxia06]

Hi Tipa, 

you are so kind. emm I found some change you made to my circuit.

1, why did you change the DC power into a DC interactive voltage? what is the difference.

2, I kept my DC power , and it seems that my circuit does not oscillate. the question is when capacitor is fully charged to nearly 1.5V and it looks like the grounding between capacitor plus and DC power impacts the total voltage output of above 2V to LED. I am not sure if grounding is the key for this voltage buidup? 

[tipa]

Конечно, на Востоке говорыят, непревоздённый, мой!, хочу тебя иметь!....
Если не согласны,-буду сотрудничать!
ГОЛУБЫЕ, И ПОЛОСАТЫЕ!
Вам, -не сюда!

[ankyxia06]

hi  Tipa, 

translated and I think you have more to add up to it. 

here I share the original textbook circuit and very successful in breadboard. hope you can help fix the simulation in Multisim. 

your posted circuit changed the structure at top right.  so hope you can help simulate this circuit and see if it works in your MS. 

[tipa]

EVERYTHING will work for us! If he doesn't want to, we'll force him!


In order not to sit out the ass, the electrolyte was reduced for the convenience of observing the blinking of the diode.
And now you think why I succeeded!
Good luck!

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[tipa]

Elimination of resistance in the Q2 collector circuit allows the use of high-power LEDs with an ignition current of 85 mA

[tipa]

You are right, the capacitor is also a voltage boost ...

[tipa]

Here is a further refinement of your circuit. Reduced the resistance in the Q2 emitter circuit, replaced the LED with more sensitive ones (less forward voltage drop)

 

[ankyxia06]

Hi Tipa, 

it judt did not work for me , could you please past your ms file on this case so I can download to see if there is something wrong with my MS.