LtSpice – Introduction

LTspice IV is a high performance SPICE simulator, schematic capture and waveform viewer with enhancements and models.

The simulator software can be downloaded from the following link:

ltspice.linear-tech.com/software/LTspiceIV.exe

The following is a circuit on how to use a switch ” .model ” in simulations, it has been created for a RC circuit.

As seen these switches are not a physical model, they require a initial voltage to start to act as one.

20150820_switch_RC is the simulation file for the given circuit, can be seen by installing LtSpice.

Every switch has some instance of resistance when on or off;
Ron = 1            ‘ the resistance when the switch is turned on.’
Roff = 10meg   ‘ the resistance when the switch is turned off.’
Vt    = 0.1         ‘ the instance when the switch turns on’

Classical way to solve the RC filter in time domain :

RC filter classical time domain way