How do you use diodes and capapcitors to switch a 4v power supply   
   so it continuously charges a battery when not being used.   
      
   I have an hp2621a terminal which had a battery to keep nonvolatile settings   
   (eg baud rate, parity &c). I want a chargeable battery to keep those settings   
   going but to charge when I have the machine on.   
      
      
      
   Decades ago someone posted how to have a bike generator charge a capcitor so   
   that when you brake, you can power a back red light.   
      
      
   --   
   	 Vasos Panagiotopoulos  panix.com/~vjp2/vasos.htm   
     ---{Nothing herein constitutes advice.  Everything fully disclaimed.}---   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)