Waveform generator electronics based on tuned LC circuits

Abstract

Disclosed is an apparatus for generating a periodically varying electrical signal for creating a periodically varying electrical field between electrodes of an ion mobility spectrometer. The apparatus includes an output port. A first tuned circuit is provided for being electrically coupled to an external power source and for, in isolation, providing a first periodically varying electrical signal having a first frequency. The first tuned circuit is coupled to the output port for providing an output electrical signal having a component at the first frequency thereto. A second tuned circuit is provided for being electrically coupled to an external power source and for providing a second periodically varying electrical signal having a second frequency different from the first frequency. The second tuned circuit is coupled to the first tuned circuit for varying the output electrical signal about the first periodically varying electrical signal.

1 . An electromagnetic transformer comprising: 
 a secondary winding comprising a plurality of turns of a first wire wound defining a core and having an approximately uniform spacing between adjacent turns;    a first primary winding comprising at least one turn of a second wire wound around the core and spaced apart from both the core and the secondary winding; and,    a second primary winding comprising at least one turn of a third wire wound around the core in parallel with the first primary winding and spaced apart from both the core and the secondary winding.    
   
   
       2 . An apparatus according to  claim 1 , wherein at least some of the core comprises a core material other than air.  
   
   
       3 . An apparatus according to  claim 2 , wherein the turns of the first wire of the secondary winding are wound proximate the core material other than air.  
   
   
       4 . An apparatus according to  claim 2 , wherein the core comprises a substantially toroid-shaped core having a gap.  
   
   
       5 . An apparatus according to  claim 2 , wherein the core material has a magnetic permeability similar to the magnetic permeability of air.  
   
   
       6 . An apparatus according to  claim 3 , wherein the turns of the first wire of the secondary winding are wound tightly around the core.  
   
   
       7 . An apparatus according to  claim 1 , wherein the approximately uniform spacing between adjacent turns of the first wire of the secondary winding is approximately equal to the diameter of the first wire.  
   
   
       8 . An apparatus according to  claim 1 , wherein the space between the first wire of the secondary winding and either one of the second wire of the first primary winding and the third wire of the second primary winding defines an air gap.  
   
   
       9 . An apparatus according to  claim 1 , wherein the first wire of the secondary winding is wound around the core over a substantial portion of a length thereof between the first end and the second end.  
   
   
       10 . An apparatus according to  claim 1 , comprising: 
 a third primary winding comprising at least one turn of a third wire wound around the core and spaced apart from both the core and the secondary winding; and,    a fourth primary winding comprising at least one turn of a fourth wire wound around the core in parallel with the third primary winding and spaced apart from both the core and the secondary winding.    
   
   
       11 . An apparatus according to  claim 10 , wherein at least some of the core comprises a core material other than air.  
   
   
       12 . An apparatus according to  claim 11 , wherein the turns of the first wire of the secondary winding are wound proximate the core material other than air.  
   
   
       13 . An apparatus according to  claim 11 , wherein the core comprises a substantially toroid-shaped core having a gap.