Lm350 power supply circuit
How can i determine the value of the R2 potentiometer for an input voltage to the regulator at 12volts and a 1.5v output voltage needed?
thanks,
Dimitri Guest
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Lm350 power supply circuit
How can i determine the value of the R2 potentiometer for an input voltage to the regulator at 12volts and a 1.5v output voltage needed?
thanks,
Dimitri Guest
Hi dimitri123
As noted in your attachment, the last term with Iadj can usually be neglected when it is small relative to the total current. In that case, the equation reduces to the following and can be solved easily for R2.
I get 24 ohms. You can check this easily with one of the online calculators, e.g. https://diyaudioprojects.com/Technical/Voltage-Regulator/
If you are looking for a potentiometer, a 50 or 100 ohm model might work well.
By the way, buck regulators are more efficient if they fit your need. That is a pretty good drop from 12V down to 1.5V.
Thank you for the quick response and the great calculations.
Thanks. A buck regulator is a nice idea.
It's a good idea to include pictures in your post by using the "Insert" function. This makes it much easier for others to see them and avoids them having to access an unknown or (in the case of anyhthing Google) a data scraping website.
The LM350 is a very old design and modern adjustable regulators don't need such low values of control resistors. (In present times you may have little choice since it's so hard to get parts.)
MK