This weekend I am trying to build a function generator that can have a selective range (frequencies are not specific, I just want to have range) between the frequency & the duty cycle. My reference manual for the NE555 timer in astable mode showed how to wire it up accordingly, and I used a 555 calculator to get a range of values for R1, R2 & the capacitor.
My thinking is this, and as such is the basis behind this whole thread, is that can I substitute R1 & R2 of fixed values, to two potentiometers? I believe this will alter the duty cycle, so to have control over frequency I want to instead use a variable/tuning capacitor. This way I have control over the entire circuit and can adjust it on the fly, without having to substitute any components.
I would like to know if this is feasible and will work. A mock up was made using my iCircuit app (which I love!) and I could only get a max of 128Hz, which is well below where I would like to get. My hope is to get a max of a couple hundred KHz or maybe 50KHz max, I'm not greedy in my selection so long as it's in the Kilohertz range I'm quite content.
My logic says this will work, as all I am doing is swapping fixed values for values that can be controlled & vary according to my projects needs and what not. However I am not familiar with potentiometers (as far as what or how high of values I should use, and I do not know how to wire up the variable capacitor, which is another thread of mine & can be viewed Here.
If a schematic is needed I will gladly post, but it is the same as the datasheet, it's just swapping fixed values for changing values.
My thinking is this, and as such is the basis behind this whole thread, is that can I substitute R1 & R2 of fixed values, to two potentiometers? I believe this will alter the duty cycle, so to have control over frequency I want to instead use a variable/tuning capacitor. This way I have control over the entire circuit and can adjust it on the fly, without having to substitute any components.
I would like to know if this is feasible and will work. A mock up was made using my iCircuit app (which I love!) and I could only get a max of 128Hz, which is well below where I would like to get. My hope is to get a max of a couple hundred KHz or maybe 50KHz max, I'm not greedy in my selection so long as it's in the Kilohertz range I'm quite content.
My logic says this will work, as all I am doing is swapping fixed values for values that can be controlled & vary according to my projects needs and what not. However I am not familiar with potentiometers (as far as what or how high of values I should use, and I do not know how to wire up the variable capacitor, which is another thread of mine & can be viewed Here.
If a schematic is needed I will gladly post, but it is the same as the datasheet, it's just swapping fixed values for changing values.
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