Schematic for LNS Technologies Levitator

This schematic is nearly identical to the 1996 Electronics Now schematic. The primary differences are:

1. Added a diode bridge, to avoid any chance of reversing the connection and destroying the 78L09 regulator. Now the full-wave rectifier will always deliver the correct polarity to the regulator. The added bridge makes this look like a classic AC to DC rectifier circuit, but the bridge is only to allow the 12VDC to work regardless of the connection's polarity.
   
2. The pnp transistor Q1 was changed to a TIP42. This transistor allows more maximum current to the coil.
   
3. The assembly has been simplified by using two PC boards. The result is a lower parts cost and the savings have been passed on to customers ($49 versus the old price of $75 US).

Last update January 17, 2007 by Barry Hansen ©1998-2007