Possible with circuit or chip

[tommyhp2]

Hi,

Is it possible to have a circuit to produce DC volts in steps (ex: 0.8, 1.6, 2.4, 3.2) with varying delays from 4.5 DC source in certain frequency? I'd like to do a lot of experiments but I don't know which voltage step, delay between the step, and the frequency which would work for the desired effect. In short, I'm doing a lot of trial and error.

How complex is the circuit? Can it be done with a programmable chip/circuit so can I feed the parameters while watching the experiment?

Thank you,
Tommy

 

[ChrisP58]

Yes. The chip you need is called a DAC, for Digital to Analog Converter. You connect it to a microcontroller and write a program to tell it what voltage you want and when to change to another voltage.

DACs have different 'bits' of resolution. A 10 bit DAC would split your reference voltage into 1024 (2^10) steps.

 

[Pommie]

How much current do you need? A DAC will give you an accurate voltage but negligible current.

Mike.

 

[rjenkinsgb]

For a few steps like that, an R-2R ladder could work OK.

Resistor ladder - Wikipedia

en.wikipedia.org

It could eg. be used to control the reference voltage to an LM317 and reduce the minimum output with a series diode or two.
And feed the ladder from say a four bit counter with an adjustable clock, for varied step rates?

 

[Xav]

Hello,

you can use directly a microcontroller that includes a DAC. By using timer, you can adjust frequency and duty cycle.