Hi ednaldocruzcorreia, Welcome to EasyEDA. Briefly: * Most of the switch symbols in EasyEDA are non-simulatable. * If you want to place a fixed position closed circuit (On) switch in a simulation then just use a low value resistor. * If you want to place a fixed position open circuit (Off) switch in a simulation then just use a very high value resistor (between about 1e9 and 1e12 Ohms). Note that simply deleting the resistor may cause problems by removing a DC path to ground. You can then run a simulation with the switch in one state then manually run another with it in the opposite state. Unfortunately it is not possible to do consecutive (stepped) simulations with the switch in one and then in the other position in EasyEDA. * If you want to *change* the state of a switch during a simulation then you have to use either a voltage (or current) controlled switch or create a switch function using a voltage (or current) controlled resistor. This may sound hard but in fact it is not. EasyEDA has simple built in voltage (and current) controlled switch elements. All you do is define the finite on and off resistances and the switch make (On) and break (Off) control voltage (or current) levels using a threshold and a hysteresis value using parameters in the right hand panel. Of course you also have to set up a controlling voltage (or current) source. Then you can run a simulation for a while with the switch in one position and then run it for a bit longer with the switch in the other position. This is for example how you could simulate the action of a momentary action pushbutton switch or a periodic sampling switch. The following examples illustrate various aspects of implementing and using switches in EasyEDA but to become properly familiar with simulation in EasyEDA, please read - and play with the linked examples referred to in - Section (3) of: https://easyeda.com/andyfierman/Welcome_to_EasyEDA-31e1288f882e49e582699b8eb7fe9b1f https://easyeda.com/editor#id=4ae6a27abf1f4a5ea9130b34c3bd92a1 https://easyeda.com/example/How_to_simulate_a_DPDT_switch-Wgs2CbLlH https://easyeda.com/editor#id=012322cf32d5446a94e001cdf4bfe381 https://easyeda.com/example/Spice_simulation_skills_02-0JjFAMKjh

@andyfierman Hi Andy, found this old thread and have tried to follow the recommendations.  Also while I cant say I have read every word of the very comprehensive Section 3 info I have read quite a bit and feel pretty comfortable with using LTSpice.  I would like to create a momentary switch for a soft latch circuit I am working on and can see there is no such thing available but do understand your recommendation here and in other posts that using a voltage controlled switch will solve my problem.  I note in your above post you say EasyEDA has VCswitches built in but not sure what that means as the only ones I can find are via the Spice Library-User Contributed and in fact have tried a couple of your models.  A problem I have when using User Contributed is I dont get any "Advanced" option in the right hand panel so cant set any parameters as I only have off/on, display and prefix. I did also follow the links but they are either broken or access denied. Hope you can again advise as you so often do. Cheers

Hi Les, Have a look at this simulation: [https://oshwlab\.com/andyfierman/Setting\_up\_switches\-oW8SPbxTf](https://oshwlab.com/andyfierman/Setting_up_switches-oW8SPbxTf)<br> <br> Hopefully that will get you going again. Switches in EasyEDA got very messed up in the transition from ngspice to LTspice... :(