can someone help me do this in falstad, thank you.

[timmychangga]

,

 

[crutschow]

No, but I can in LTspice, if that helps.

 

[timmychangga]

No, but I can in LTspice, if that helps.

sure, i really need it for my project : (
i also have to put combinational logic in that circuit which is kinda complicated

 

[ChrisP58]

sure, i really need it for my project : (
i also have to put combinational logic in that circuit which is kinda complicated

Then you should first create a sequential truth table or a state drawing to show what your circuit needs to do.

 

[Tony Stewart]

You have no control signal nor a feedback signal and no transfer function defined, thus it won't work.

After this is defined, you might be able to control it. I suggest both current feedback and a tach feedback to make it stable.

Also you cannot control both directions with 1 transistor. You need 4 in a full bridge.

 

[rjenkinsgb]

You have no control signal nor a feedback signal and no transfer function defined, thus it won't work.

After this is defined, you might be able to control it. I suggest both current feedback and a tach feedback to make it stable.

Also you cannot control both directions with 1 transistor. You need 4 in a full bridge.

It's feeding a radio control servo - the position is defines by the pulse duration.
(Usually 1 - 2mS range, with 1.5mS being centre of travel).

They are supposed to have a continuous pulse train with ~20mS repetition rate, though. The behaviour cannot be guaranteed if the pulses stop, as they would do with that circuit.

 

[Pommie]

I think the OP is controlling a model servo which requires pulses between 1 and 2 mS and has all the feedback built in.

The circuit appears to produce 1 or 2mS pulses depending on which button is pressed. This should be producing pulses every 20mS and some servos don't like if the timebase is different.

There's a similar thread from a long time ago here.

Mike.
P.S. sorry JR (or RJ) typed this about 6 hours ago but didn't post it.

 

[Tony Stewart]

oyh.. that servo

Wikiwand - File:Servomotor_Timing_Diagram.svg

File:Servomotor_Timing_Diagram.svg

www.wikiwand.com

R values can be changed if a 15k pot is not available but here it needed 12.5 k to 25k to get 5 to 10% d.f. at 50 Hz
my design simulation

 

[timmychangga]

thank you so much for helping, i am just struggling because i am a college student in philippines and that is our project

 

[Nigel Goodwin]

thank you so much for helping, i am just struggling because i am a college student in philippines and that is our project

Why not just google for '555 servo tester' there have been countless examples over the decades.

 

[timmychangga]

Why not just google for '555 servo tester' there have been countless examples over the decades.

i googled also but some of it were too complicated and some were intentionally made wrong which is hard for me to identify

 

[Pommie]

Tell us what you are trying to do and we may be able to help.

Mike.

 

[timmychangga]

i have to do a combinational logic, a flipflop and a servo (like in the picture) in a one circuit

 

[Pommie]

Does the servo have to move?

Mike.

 

[timmychangga]

yes

 

[Pommie]

Can't help with Falstad - don't even know what it is.

I'd approach this as needing a pulse every 20mS - a 555 setup to produce 50Hz will do this - positive edge every 20mS.
Use the pulse to trigger another 555 to output a 1mS pulse.
Have a push button that changes the period of the second 555 to 2mS.

Button release = -90 degrees.
Button pressed = 90 degrees.

Mike.

 

[timmychangga]

thank you so much but what does the schematic looks like and what are the connections

 

[Tony Stewart]

thank you so much but what does the schematic looks like and what are the connections

I posted it already ! https://www.electro-tech-online.com...this-in-falstad-thank-you.165739/post-1447052 in Falstad !!

 

[timmychangga]

oh im sorry, thank you so much!