high voltage driver

 |                                           >             
gnd                                          >R1        
                                             >              
                                             |   
                                             |B        
                                            ---      GND 
           T1:NPN Power Transistor:2N3055  C/ \E     | 
                                           /   \     |
                                          | TVS |    |
                                      ----+->|<--+----+

TVS: This is a back EMF snubber. It may composed of a variety of components to suit. Sometimes you see zeners, or RC circuits, or transorbs (transient voltage suppression diode). Transil diodes provide high overvoltage protection by clamping action -- Part number 1.5KE15CA

A neon indicator bulb with a resistor in place of the TVS can be used to indicate when EMF is over 100 V.

Designing RC Snubber Networks

media:igbtAPPguide.pdf

Misc notes

L = N<sup>2</sup> * p * A / l

• L = inductance in Henrys
• N = number of turns of wire (straight wire = 1)
• p = permeability of the core material
• A = are of the coil in square meters
• l = average length of coil in meters.