EEVblog® Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: IO390 on February 13, 2014, 07:27:21 pm
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I've built the circuit attached to this post. The inductor is hand wound on an amorphous core, and measures just under 32uH.
When I first turned on the circuit, I had the current limit set to 500mA and it instantly went up to the limit.
When the inductor is removed but all the other components left in place, the circuit draws about 120mA.
Can anyone think of a reason as to why this is? The schottky diode hasn't yet arrived, so I substituted it with a 1N4007. This being said, when I remove the diode but leave the inductor in place, the circuit pulls the PSU to the current limiter. Is this just because the inductor is hand wound, or is maybe saturating?
Thanks in advance.
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When the inductor is removed but all the other components left in place, the circuit draws about 120mA.
not normal ...
The schottky diode hasn't yet arrived, so I substituted it with a 1N4007.
:palm: that 1n4007 is so slow it will never come out of conduction !
when I remove the diode but leave the inductor in place, the circuit pulls the PSU to the current limiter. Is this just because the inductor is hand wound, or is maybe saturating?
you essentially cut off the feedback so the switcher keeps pumping because it doesnt see an output voltage : eventually it saturates the core.
As for the hand wound inductor .... i wouldn't trust that as far as i can throw it. do you know the magnetic properties of that core ? did you calculate the saturation current for your hand wound inductor ?
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Thanks for the reply. I'll get a proper inductor and try again.