From: gorplop@sdf.org   
      
   On 24.02.2020 18:27, Steve Wolf wrote:   
   > Just for fun I thought I would make a wireless phone charger. I'm not really   
   going to use it but I wanted to build it and just see if it actually worked.   
   The circuit uses two coils and a 2n222 transistor very simple.   
   >   
   > Well I can't really get it to work maybe I could get half a volt maybe to   
   past through induction. Then it seems to stop. I connected my meter to the   
   receiving coil to test.   
   >   
   >   I was using 30 gauge wire which I had although the circuit calls for 32   
   gauge that may be part of the issue.   
   >   
   >   However my question is , as I began to think about it and a little bit of   
   science that I know is that induction I thought had to be AC current because   
   there had to be movement caused by ac going up and down. The circuit as far as   
   my reading however    
   puts in 5 volts DC in the Base unit and passes it to the receiving coil. I'm   
   not sure if that's going to work?   
   >   
   > The question then is, in a simple circuit can you use DC in induction.   
   >   
   > Thanks   
   >   
   No, you can't use DC here. In fact you should not have any DC on the   
   coil... If you put DC in it you would get an electromagnet (or a lot of   
   smoke). What frequency are you driving your coil at? How many windings   
   does the each coil have?   
      
   QI chargers usually work at between 100 and 200 kHz for low power and   
   ~500kHz for medium power.   
      
   Cheers, Nife   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)