Frequency and Duty seperate

[wijnendael]

This is my first post on the forum and would like some advise on building a circuit that will allow me to adjust the frequency and duty cycle independantly. Most of the circuits i find will alter the frequency when the duty is adjusted, is there a way to do this and could somebody point me to any example circuits of this. I would ideally like to have the frequency in a range of around 25-200hz and a duty of around 0-100%. Is this possible ? and have it adjustable on the output of a variable power supply of 0-15vdc, any help would be appreciated.

 

[Golden Electronics]

Yes it is possible using controller

 

[wijnendael]

thanks for the reply golden electronics but being a novice to all this i am not sure what you mean by a controller. I would really like to build a circuit that will give me indepenent control of the frequency and duty in the ranges i stated above and would really appreciate some help or examples on how to achieve this if possible. I find the quickest way of learning is by trying to understand the way that more professional people acheive things

 

[FvM]

It's also possible using an oscillator circuit to generate the frequency and a separate monoflop to generate the duty cycle. Or a ramp/triangle generator and a comparator.

 

[wijnendael]

FvM would these circuits be made using simple 555 timers or something different, can you give me a link to any example circuits to get me started ?

 

[FvM]

555 is an option. The application circuits in 555 data sheet should give you an idea how to make astable and monoflop.