Spice-Simulation Using LTspice Part 2 - IEC & Associates

Step 3:Open „Edit / Attributes“, but now choose „AttributeWindow“. Click on „Value“ in the list and place“SCR“ beside the symbol. Repeat the procedure for„SpiceModel“. This should be the result.Now the finished symbol must be saved in a newfolder (named „Thyristors“) in „lib / sym“using the name 2N5171.asy“.--------------------------------------------------------------------------------------------------------------------------------------12.2. Switching Resistive LoadsDescription:A sine wave source V1 (peak value = 325 V, frequency = 50Hz) feeds a series connection of a resistor R1 (100) and the thyristor 2N5171. Between the gate and the source a resistor R2 (1k) is added to the schematic. Apulse source V2 is connected to the gate of the thyristor using a “current limiting resistor R3 with 10”.Explanation of other entries on the schematic::a) „.tran 100m“ gives a simulation time from 0.....100ms.b) „.include thyristr.lib“ prepares for the usage of the library with the thyristor SPICE-Models.c) The pulse voltage at the gate is programmed by the line:PULSE (0V 4V 5ms 0.1us 0.1us 10us 20ms)This gives a minimum amplitude of 0V and a maximum amplitude of +4V. The start delay time is 5ms, therise and fall times are 100ns. Pulse length is 10µs with a period of 20ms.78