I have built a voltage regulator based on the following circuit:
http://www.circuitstoday.com/3a-switching-regulator
with a few alterations: Q1 is a TIP42G; L1 is an unknown but large value; D1 is a Schottky dual 15 A common cathode; everything else is essentially the same. The problem I'm encountering is that I am not getting the amperage expected through the regulator. I could only get 450 mA through a charging circuit to a Kindle from a solar panel putting out 2.5 amps. I suspect that the power transistor is not fully turned on, but I'm not sure. Any advice?
http://www.circuitstoday.com/3a-switching-regulator
with a few alterations: Q1 is a TIP42G; L1 is an unknown but large value; D1 is a Schottky dual 15 A common cathode; everything else is essentially the same. The problem I'm encountering is that I am not getting the amperage expected through the regulator. I could only get 450 mA through a charging circuit to a Kindle from a solar panel putting out 2.5 amps. I suspect that the power transistor is not fully turned on, but I'm not sure. Any advice?