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Topic: Identifying my LCD (Read 1 time) previous topic - next topic

Paul__B

That circuit should work as far as I can see, but you could do just as well by arranging one Arduino pin to be continuously generating a square wave output and driving the "pump" with the two capacitors and two diodes.

Since the current requirement is so low and you can "pump" at a high speed, you could use 1N914 or similar diodes and 1µF capacitors.

zsiti4


That circuit should work as far as I can see, but you could do just as well by arranging one Arduino pin to be continuously generating a square wave output and driving the "pump" with the two capacitors and two diodes.

Since the current requirement is so low and you can "pump" at a high speed, you could use 1N914 or similar diodes and 1µF capacitors.



Thx for the information but my question is still upp. Why the negativ voltage dropping in the circuit? I drive it with a transformator powered 12V 1A standard power supply. I dont want to use en arduino pin for this purpose.

Paul__B

According to my mental arithmetic, with the components you specify, that circuit will oscillate at upwards of 50 kHz.  If you are using silicon power diodes of the 1N4004 sort, they cannot switch at (anywhere near) that speed, so they capacitively load the circuit instead of rectifying.   I think you might do a lot better using 1N914/ 1N4148  diodes and 1µF capacitors and use a 0.047µF capacitor for the time constant.

In any given design, you may have an Arduino pin that is continuously being clocked at a relatively high frequency which you could use to drive the "pump".

zsiti4


According to my mental arithmetic, with the components you specify, that circuit will oscillate at upwards of 50 kHz.  If you are using silicon power diodes of the 1N4004 sort, they cannot switch at (anywhere near) that speed, so they capacitively load the circuit instead of rectifying.   I think you might do a lot better using 1N914/ 1N4148  diodes and 1µF capacitors and use a 0.047µF capacitor for the time constant.

In any given design, you may have an Arduino pin that is continuously being clocked at a relatively high frequency which you could use to drive the "pump".



Thanks again but i have not the knowledge for the replacing. Im good at the programming but not with the circuits itself. Can i ask you to draw a circuit with your components? Or replace them in my circuitdrawing? Sure i used 1N4001 diodes. Is it better with this diodes? http://media.digikey.com/pdf/Data%20Sheets/Rohm%20PDFs/RB050LA-40.pdf

Paul__B


Can i ask you to draw a circuit with your components? Or replace them in my circuit drawing? Sure i used 1N4001 diodes. Is it better with this diodes? http://media.digikey.com/pdf/Data%20Sheets/Rohm%20PDFs/RB050LA-40.pdf


And I'm not so good at circuit drawing (which is to say with whatever software you might have used, I am not familiar).  :)

Given the circuit you posted, the capacitors that are too large and could be replaced with 1µF are the two on the right hand side, while the 0.047µF capacitor would be that on the left hand side.

I cannot say whether the Schottky diodes you cite are suitable or not as the data sheet make no mention of recovery time.  I presume however that means they are not suitable, and you should use 1N914/ 1N4148 s.

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