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SK40 and Voltage regulator

PostPosted: Sat Nov 24, 2012 6:43 pm
by alongpali
I am using 12V supply towards sk40.
using a multimeter, Vdd output for sk40 is approximately 5V.
I need to step down 5V to 3V as output.
So that, I am using voltage regulator (LM317).
The PROBLEM is, when I try to switch on the voltage regulator, Vdd output drop from 5V to 1.6V.
1.6V reading I gain from A point. No voltage at B point.
This is the diagram for my voltage regulator.
It is about the capacitor?

Re: SK40 and Voltage regulator

PostPosted: Sat Nov 24, 2012 7:16 pm
by zhenning
alongpali WROTE:I am using 12V supply towards sk40.
using a multimeter, Vdd output for sk40 is approximately 5V.
I need to step down 5V to 3V as output.
So that, I am using voltage regulator (LM317).
The PROBLEM is, when I try to switch on the voltage regulator, Vdd output drop from 5V to 1.6V.
1.6V reading I gain from A point. No voltage at B point.
This is the diagram for my voltage regulator.
It is about the capacitor?


Hi,

Did you read the datasheet of LM317?

ScreenHunter_12 Nov. 24 19.10.png


The LM317 middle pin is adj that allows you to adjust your Vout. Are you sure you connect the pins correctly?

Re: SK40 and Voltage regulator

PostPosted: Sat Nov 24, 2012 7:46 pm
by alongpali
My apologies.
I thought, the LM317 is similar with LM7805.
Thx for your concern~ 8-)