Flip-Flop Circuit, build and demo

[IBreedBassetts9C]

Am I correct in assuming that when (at 4:22) the 100 ohm resistor comes into play the junction between the top of the resistor and the emitter becomes more positive, thereby inducing electrons to travel from the negative side of the capacitor, thru the base (of the transistor on the right side of the scematic) and emitter and finally the resistor? Or is it that the capacitor has no other path than to discharge thru the resistor? Just curious.

[AllAmericanFiveRadio]

@IBreedBassetts9C

When the 100 ohm resistor is back in the circuit this produces a voltage drop. The capacitor is charged with out a voltage drop. When the resistor is back in the circuit the voltage drop across the base-emitter junction is high enough to forward bias it, driving the transistor into saturation.

[fingerboy18]

Phenomenal demonstration. You explain things very clearly. Keep it up!

[AllAmericanFiveRadio]

Thanks fingerboy18

[fingerboy18]

@AllAmericanFiveRadio You're welcome. As an electrical engineer, I've never even seen this circuit! I'm always astonished to learn new circuit configurations. Take care.

[hardstyle905]

@fingerboy18 then what the hell are you learning there? a bistable multivibrator is one of the most basic circuits.

[fingerboy18]

@hardstyle905 Mostly multi-stage amplifiers considering bandwidth and impedance, signals and systems, electromagnetics...

Chances are is that I simply forgot since it was likely a few years back when I learned this.

[PoirierMike]

excellent explanation!

Love it!

[AllAmericanFiveRadio]

Thanks PoirierMike

[SpeakerFreak95]

very very nice video!

[AllAmericanFiveRadio]

Thanks SpeakerFreak95

[KyleCarrington]

Very interesting. Beyond changing which LED is illuminated, what is this circuit often used for?

[AllAmericanFiveRadio]

@KyleCarrington

Memory and logic, A NotA, CPU....

[KyleCarrington]

@KyleCarrington How important is it to have the same load on both sides, i.e. could you have a 10 LED load on one side, and just 3 on the other... or would that not work at all. Thanks

[THEtechknight]

and without this circuit, microcomputers would never work.

[AllAmericanFiveRadio]

Thanks THEtechknight

[THEtechknight]

@THEtechknight And when your attacking microprocessors for glitch flaws, its these circuits that you target.

[PihkalTheTihkal]

Another great informative video.

Thanks!

Keep up the good work.

[AndyDaviesByTheSea]

Hi Rick, nice demo again.

Kind Regards ... Andy

[AllAmericanFiveRadio]

Thanks AndyDaviesByTheSea

Thanks Andy,

I tried an oscilloscope and a digital meter to show the negative pulse. The scope was to fast and the digital meter would not show the same results each time, the pulse was not long enough. The analog meter worked great for the demo.

Regards

Rick

[AndyDaviesByTheSea]

@AllAmericanFiveRadio Hi Rick, I’m sure we learn a lot from creating the video’s as it’s only when you have to ‘Prove it’ that you realise some of the little intricacies for yourself, well that’s how it works for me hi hi.

Kind Regards ... Andy

[maahal]

Very nice explanation of that circuit. Your videos are great.

[AllAmericanFiveRadio]

Thanks maahal

[kitzenmovies]

Thx all americanradio! I always wanted to know how flip flops work...it's one thing to see how they are built to actually be explained how they work! Thx keep up the awesome videos please!

[AllAmericanFiveRadio]

Thanks kitzenmovies

[ElectricSparq]

Thanks for this.

[AllAmericanFiveRadio]

Thanks ElectricSparq

[mediaguardian]

Hi,

I enjoy your videos and am trying to learn electronics (I am a retired computer scientist). I am trying to figure out the difference in the voltages when the led is lit. Am I to assume the ground-base voltage takes into account the voltage drop across the 100ohm resister whereas the emitter-base voltage doesn't? Also, what is the significance of the 10K resisters in parallel with the caps? Could they be 5K or 20K?

Thanks,

Jim

[AllAmericanFiveRadio]

Thanks mediaguardian

Yes thats right on the ground-base voltages. The 10K supplies the + voltage to turn on the transistor. The cap supplies the - voltage to turn off the transistor. If the 10K was changed to a resistor to high it would not turn on the transistor. If to low it would keep the transistor on.

[lawnmowerrecycler]

Very nice demo as usual, thanks.

[AllAmericanFiveRadio]

Thanks lawnmowerrecycler

[engmustafa83]

How many volts are the capacitors' volt

I just tried the circuit but it didn't work :(

and can you please tell me what is the transistor, LEDs you're using?

thank you so much

[khoham]

@engmustafa83 What needs to be right is the capacitance not the volts.. You only need to meet the voltage threshhold.. the capacitance needs to be correct.. or you can just look for the basic multivibrator circuit

[engmustafa83]

@khoham thanks a lot for this reply,

but I'm afraid that i don't agree with you

the capacitor voltage and the type of transistor as well as the LEDs is playing a sensitive rule here

if you didn't put the same or closer to it the circuit never work

[khoham]

@engmustafa83 look up what you can on capacitance..

[AllAmericanFiveRadio]

Thanks engmustafa83

The transistors are 2N2222, both about 210 beta. All resistors are 5%. The caps are 10WVDC. Like I said in the video it did take me a little time to get this to work. I had to swop out a few parts to get thinks to match.

[manojsam79]

Good explanation

[AllAmericanFiveRadio]

Thanks manojsam79