<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div style="font-family: Calibri, sans-serif; font-size: 14px;" id="yui_3_16_0_1_1442821476079_3073" class="">Hi,</div><div style="font-family: Calibri, sans-serif; font-size: 14px;" id="yui_3_16_0_1_1442821476079_3075" class=""><br id="yui_3_16_0_1_1442821476079_3077" class=""></div><div style="font-family: Calibri, sans-serif; font-size: 14px;" id="yui_3_16_0_1_1442821476079_3079" class="">I need to model the current in a solenoid. I would use a resistor with the standard inductor model but the inductance changes considerably with position of the solenoid plunger (as the solenoid is closing). The standard inductor model only accommodates a fixed inductance.</div><div style="font-family: Calibri, sans-serif; font-size: 14px;" id="yui_3_16_0_1_1442821476079_3079" class=""><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px;" id="yui_3_16_0_1_1442821476079_3079" class="">The equation for inductor current is:</div><div style="font-family: Calibri, sans-serif; font-size: 14px;" id="yui_3_16_0_1_1442821476079_3081" class=""><br id="yui_3_16_0_1_1442821476079_3083" class=""></div><div style="font-family: Calibri, sans-serif; font-size: 14px;" id="yui_3_16_0_1_1442821476079_3085" class=""> I(t) = (V/R)[1-eˆ(-Rt/L)]</div><div style="font-family: Calibri, sans-serif; font-size: 14px;" id="yui_3_16_0_1_1442821476079_3087" class=""><br id="yui_3_16_0_1_1442821476079_3089" class=""></div><div style="font-family: Calibri, sans-serif; font-size: 14px;" id="yui_3_16_0_1_1442821476079_3091" class="">Anyone have any suggestions?</div><div style="font-family: Calibri, sans-serif; font-size: 14px;" id="yui_3_16_0_1_1442821476079_3093" class=""><br id="yui_3_16_0_1_1442821476079_3095" class=""></div><div style="font-family: Calibri, sans-serif; font-size: 14px;" dir="ltr" id="yui_3_16_0_1_1442821476079_3097" class="">Thanks,</div><div style="font-family: Calibri, sans-serif; font-size: 14px;" dir="ltr" id="yui_3_16_0_1_1442821476079_3097" class=""><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px;" dir="ltr" id="yui_3_16_0_1_1442821476079_3097" class="">Mike Greenish</div></div></body></html>