Hello,

I've built this circuit and have a question.

http://www.jtkit.com/Schematic.html

At Vout I read 29v. I put a load of just one small 3mm red LED. It blinks for a second then the voltage on Vout drops dramatically to less than 1v. What I'm trying to do is build a dirt battery that can use this circuit to power a LED for my daughter's science fair project. Currently I'm testing with 1 1.5v AA.

Is there a possible component failure?

Also, I would like to simulate this in Multi-Sim but can't find the component for the iron core inductor. Is it possible to create it?

Thanks,
Chris

 

Does the circuit work in regulated mode? i.e. with the jumper switch connected.

Are you including a series resistor with the LED when connecting as a load?

 

In regulated mode it will output 2.8v. I am not including a series resistor. Should I? Value?

 

A series limiting resistor is a good idea. Try 100Ω 0.25W as a start.

The voltage is probably dropping out because the load current is too high with the unlimited LED. If 100 ohm doesn't work try something higher - 220 ohm etc.

 

Thanks. I had a 150. I think the LED was failing. I pulled another one and it works great.

At 150 the voltage is 3.75v

Chris