Common mode choke model

XXsnip

Thanks for that - much appreciated. Regards Anthony

Just use two inductors and couple them using a K directive.

Save the following as a .asc file and open it with LTSpice and you'll see:

Version 4 SHEET 1 880 680 WIRE -240 240 -240 208 WIRE -240 352 -240 320 WIRE -112 352 -112 320 WIRE -64 208 -240 208 WIRE -64 320 -112 320 WIRE 128 208 16 208 WIRE 128 320 16 320 WIRE 224 208 128 208 WIRE 224 320 128 320 WIRE 352 208 304 208 WIRE 352 320 304 320 FLAG -240 352 0 FLAG -112 352 0 FLAG 128 208 out1 FLAG 128 320 out2 FLAG 352 320 0 FLAG 352 208 0 SYMBOL ind2 -80 224 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L1 SYMATTR Value 100µ SYMATTR Type ind SYMBOL ind2 -80 336 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L2 SYMATTR Value 100µ SYMATTR Type ind SYMBOL voltage -240 224 R0 SYMATTR InstName V1 SYMATTR Value ac 1 SYMBOL res 320 192 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R1 SYMATTR Value 50 SYMBOL res 320 304 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R2 SYMATTR Value 50 TEXT -88 264 Left 0 !K1 L1 L2 0.9999 TEXT -160 48 Left 0 !.ac dec 100 100k 100meg

Cheers, Jeroen Belleman