EveryCircuit - Astable flip flop

11 years ago

Change caps to 1uf and change batt to hz then ms and back to volt. Adjust volt to app 7v,wait and see what happens

11 years ago

Then adjust the simultain speed with the clock( go faster)

11 years ago

thanks for the help! not working yet but ill keep trying cycling those changes for a bit... is that a known workaround for Everycircuit? (PS: working example of basically same circuit with same values http://everycircuit.com/circuit/5144392801189888)

Opium

11 years ago

oooo it's working now thanks heaps!! that wouldve driven me nuts for a while... I still don't really understand... i've got it all back to how i had it originally, it's like i've just "tricked" everycircuit in to emulating the "slight differences between legs" that the real world uses to decide which flips or flops first? Is that right?

dmayan

11 years ago

If you inject noise by draging the sketch around, it begans to work ;)

Opium

11 years ago

Thanks dmayan, will keep that in mind. For the other folks coming across this: just cycling the speed a few times seems to work too...

Sine_eyed

11 years ago

You've almost got it, but the circuit is struggling with those 100uF caps at only 5 volts. Also, putting that resistor on the scope won't help you much in understanding this circuit. Instead, scope the base and collector nodes of each transistor. Here's a quick recipe that's close to where you're at: 9v - 330R - 10K - 47uF. Trust me..

Opium

11 years ago

thanks ill try it! im really loving this everycircuit community... much appreciated all

Mamish

11 years ago

I've noticed it works immediately if you change one or both 10k resistors to 20k. I'm not entirely clear what the purpose of those resistors is so I can only guess they're pulling the BJT base voltage too high on 10k.

Sine_eyed

11 years ago

I think you're right on the money @Mamish, those are pull up resistors. Also, while it seems to be working, the recipe I gave was slightly wrong (i was recalling from memory way back to my very first blinkie). It should be 330R, 47K and 10uF instead.

Sine_eyed

11 years ago

I think you're right on the money @Mamish, those are pull up resistors. Also, while it seems to be working, the recipe I gave was slightly wrong (i was recalling from memory way back to my very first blinkie). It should be 330R, 47K and 10uF instead.

Sine_eyed

11 years ago

The 330R value I suggested is for the LEDs' current limiting resistors, and was calculated for 9volts. @Opium- the astable multivibrator is pretty flexible as far as circuits go- the values I offered are just one of many working combinations. However, there are even more ways to screw it up lol! So put this simulator to good use and experiment! Take a look at my profile page for clues and/or ideas for your future blinkies..

waynewec

11 years ago

The 10k and 47uF components set the time constant of the circuit. Changing those changes the frequency and having them uneven will affect the duty cycle by changing the time constant for each aide independantly