# How to find the time taken for the output to reach a certain value in LTSPICE? [duplicate]

This question is software related. I just wanted to know if it was possible to get the time at which my circuit reaches a certain value without just running the cursor and getting a approximate value. For example if I have a RC circuit , plot the time at which the voltage across resistor reaches 1/2 * Vdd. Is there someway to do code it and get the exact answer? if yes can you please explain how it can be done?

• Yes, it's called circuit analysis. For simple circuits- you can derive an equation representing the time domain response; then simply solve that equation for your conditions, e.g. time at Vout = Vdd/2.
– user16324
Commented Jun 30, 2021 at 16:37
• For sure you can do it try to read here ltwiki.org/LTspiceHelp/LTspiceHelp/… and here youtube.com/watch?v=GtRaEHhMeCE
– G36
Commented Jun 30, 2021 at 16:44
• Aagh? I want to get it solved with LTSPICE not pen and paper. From my simulation results I want to find the time taken to reach a certain point @user_1818839 Commented Jun 30, 2021 at 16:45
• @HariKrishna What do you mean by "plot the time at which the voltage across resistor reaches 1/2 * Vdd"? A .TRAN simulation is done in a range of time, anything plotted will be a function of that whole timespan. Did you mean that you wanted your simulation to stop when it reaches that value? Otherwise, this might help. Commented Jun 30, 2021 at 16:54
• You want to use the .measure statement to automate such measurements. You should be able to search for examples using that keyword. Commented Jun 30, 2021 at 17:26

.meas TRAN newsignal2 FIND time WHEN 0.5=V(vout)