PWM and old school...

[MMDuino]

Dears

How could i generate PWM through 3 pins rotary by using only transistors, OPamps, 74xx and 40xx.. i mean without microchips...??

could anyone help me in this issue...

[bugs]

Is this a school assignment?

[Cherry]

Maybe you can ask professional people's advice.

[Delta]

If you aren't using microchips, then opamps, 74xx and 40xx series logic are out of the window!  And what on earth do you mean by "through 3 pins rotary"?

PS. Do your own bloody homework!

[Simon]

errr 555 timer ? there are other more elaborate ways with opamps but you'd need to understand the various circuit topologies to put together am opamp version

[madires]

LM339 or TL494 for example.

[MMDuino]

Indeed, it's bloody homework!

[rob77]

you mean a 3pin rotary encoder with quadrature output ? that would be a challenge without a micro.
if you just need a PWM generator, then 555 - google for "555 servo tester"

[Zero999]

I think some of the meaning has been lost in translation.

Presumably by no microchip, you mean no microcontroller?

Are you talking about using a potentiometer to control the duty cycle of a PWM signal?

Here's how to do PWM with commonly available ICs:

555 Timer


LM393, comparator


CMOS logic gates


https://www.eevblog.com/forum/projects/pwm-signal-from-555-timer/msg17855/#msg17855

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It's also possible to so this with discrete transistors but I don't have the circuit handy at the moment.