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Norbert

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2019.06.01 01:53:38 (UTC+1)
Name: João

Comment:
Help me. I am Burro.

Me: We are all born as burros. Human brains are made for learning which helps to get out of that missery ;-)

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2018.11.15 17:05:15 (UTC+1)
Name: lucky

Comment:

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2018.11.10 03:31:50 (UTC+1)
Name: Lucky

Comment:
Please help me,  i want to make a flip flop with 4 input and 4 output,  when one is on state rest goes off automatic.

Me: You could switch a 5 input OR gate in front of the reset inputs of your flip flops and connect four of each inputs with the output signals and use the remaining to reset with an external signal.

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Seite: technics-base-circuits-multivibrator_ge.htm
Datum: 2018.10.30 03:06:01 (UTC+1)
Name: Ingo

Kommentar:
Hallo Norbert,

Danke für Deine Erklärungen.
Wenn es möglich ist, bitte ich
darum, zu erfahren, welchen Einfluss der Verstärkungsfaktor der Transistoren auf die maximal mögliche Schaltfrequenz der astabilen Kippstue hat.

Sind mit kleinerem Verstärkungsfaktor höhere Frequenzen möglich ?

Mit freundlichen Grüßen

Ingo

Me: Bitte gerne.
Der Verstärkungsfaktor ist da nicht so ausschlaggebend, sondern wie schnell die Transistoren oder der Operationsverstärker schalten kann. Die Schaltfrequenz beziehungsweise die Flankensteilheit des Ausgangskreises ist das entscheidende Kriterium.


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Page: technics-base-circuits-multivibrator_en.htm
Date: 2018.01.11 10:08:44 (UTC+1)
Name: loll

Comment:
In German please

Me: Simply click on the German flag on top of the page.

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2016.07.15 07:02:17 (UTC+1)
Name: Thomas Hoffmann

Comment:
Hello
i am intereste in Mosfet astabile Vibrator- what is the supply voltage?

Thanks

Me: 5V to 12V. More will destroy the 2N7000.

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2015.07.19 at 20:48:05 (UTC+1)
Name: Daniel

Comment:
I think you misunderstood me. My fault because I didn't mention that what I explained was the second half of the cycle, it was after T1 just closed. So the Gate-Source capacitor must have discharged in order to T1 get closed. I said that it could be through the(now) opened T2 and C2. If it yet semms wrong to you, would you tell me where the electrons come from to the pozitively charged gate? And i would have more two questions if that does not bother you!

Me: With T1 is "closed" you mean it is turned "OFF"? Yes, whenever T2 is turned "ON", the gate-sorce line of T1 is shortened, thus the gate "capacitor" gets discharged through the source-drain line of T2.

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2015.07.19 at 20:08:42 (UTC+1)
Name: Daniel

Comment:
Great work, as always!
I recently sterted studying MOSFETs and analyzing their working in the particle level. I looked at the MOSFET type astable. m. and realised that i don't know how or what shuts down T1 when T2 opens. I just want you to look at my explanation. So: When T2 opens it starts to conduct and basicly T1 from Gate to Source is almost like a capacitor so from the superposition of that "capacitor" T2 in series with C2 looks like a short circuit so it discharges itself. Am I correct?

Me: Thanks! The capacitance at the source pin of a MOSFET is negligible compared to 0.33μF of C2 used in the circuit of Figure 24. That tiny capacitance doesn't "shorten" C2, thus you are wrong. Even if the capacitance at the gate was larger, the effect was that there is a second capacitor switched in parallel to C2, thus that capacitance would become larger resulting in a lower frequency.

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2015.06.08 at 19:56:25 (UTC+1)
Name: Pk. D

Comment:
Hi, I see that you have used an electrolytic in your Transistor circuit of astable multivibrator . How is that possible, when I do that , I get a whole lot of noise(I connect output to a speaker)? After prolonged periods, the Capacitor even ends up Burning on itself.

Me: A loudspeaker is a too heavy load at the output of that circuits! Use LEDs or an oscilloscope to visualize the functionality. with electrolytic capacitors you have to note the correct polarity (negative terminals of the capacitors to base of transistors). You can't use electrolytic capacitors in the MOSFET circuit!

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2015.06.08 at 19:53:09 (UTC+1)
Name: Pk. D

Comment:
Hi, I just want to know if an Electrolytic Capacitor can be used in the astable OpAmp circuit.
Thanks!

Me: Not in the circuit of figure 25, since the polarity is swapped at the terminals of the capacitor during operation.

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2014.12.06 at 10:02:27 (UTC+1)
Name: SuperFabius

Comment:
Hi,
I've found this site googling about an astable multivibrator with Mosfet, because I want to make a test PCB using only SMD components.
Until now I've only some 2N7002 SOT23 plus various 0805 resistors, capacitors and leds... Just to play with my new AOYUE 852A++ rework station.
If I've time, I want to make a little blinking Christmas tree (USB powered) using only discrete devices, just to refresh some theory...
Your site is really very well done (the best I've found)!

Me: Thanks! And if you run in trouble when doing the reverse engeneering of my multivibrator circuits, let me know.

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2014.12.01 at 11:41:07 (UTC+1)
Name: Prathik Diwakar

Comment:
Sir,
Thanks for your effort-very good website.
In this page, in your example circuit, you have printed Frequency of multivibrator as 0.83Hz and time period as 15ms.
For 0.83 Hz, time period =1.2s,
And for time period 15ms, frequency=66Hz.
Thank you!

Me: Yes, the frequency was wrong, it is indeed 66.67Hz. I have fixed that - Thanks!



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Page: technics-base-circuits-multivibrator_en.htm
Date: 2014.11.22 at 15:47:55 (UTC+1)
Name: Dlect

Comment:
Thank you so much for the clear explanation, I was trying to understand the multivibrator circuits for months, but always it was so confusing. But after reading your tutorial now I'am beginning to understand it. thank you so much for the effort you put to prepare this tutorial.

Me: You're welcome! And if there is still something you don't understand, leave another comment.

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2014.09.22 at 00:25:35 (UTC+1)
Name: wdog

Comment:
hi. nice work!

I'm e newbie, can you explain how to setup the values of the resistors for a flip flop ( es. Vcc = 5v, two BC547 and 2 LED 1.8V 20mA )?

I need some examples of circuit analysis. it's really hard to begin :D

can you help me?
thanks a lot

Me: Sorry but I can't spend my time with answering questions like that. Please use one of the example circuits given in the chapter or ask that question in one of the electronics fora available on the net. Or simply use the values of the example circuit and replace the LEDs / transistors with your devices and see what happens (the risk of damaging your devices is low, since the resistors are relatively high, the series resistor of the LEDs (R3) must match the maximum current listed in the datasheet).

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2014.09.17 at 15:59:21 (UTC+1)
Name: Roby

Comment:
Hi!
You made a great work!
But how can i obtain a bistable multivibrator with operational amplifier?
I need  output of the operational on at the first push on button, off at the seconcond push and so on...
In practice: 1 0 1 0 1 0 and go.
Thanks for your attention.


Me: Thanks! What you are looking for is a T flip-flop as described in the chapter about computer circuits. I have never built one using only op-amps and I guess it's not too easy, so I recommend buy a T flip-flop IC as this is the cheapest solution.

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Page: technics-base-circuits-multivibrator_en.htm
Date: 2014.07.27 at 01:44:43 (UTC+1)
Name: Vinod Kumar

Comment:
The astable multivibrator Circuit Published is working superbly
great work
thanks

Me: Excellent!
...and if one of the circuits doesn't operate as intendet, leave another comment or send a mail.