I started using Ltspice because most of the users here recommendded it.. now im trying to view the transient curve of a voltage of a capacitor when a dc voltage is applied..
for this i used a voltage source with a pulse of 5 volts and a 10 k resistor in series with a 1n capacitor.. but in the process of charging the capacitor the curve is a line instead of the exponential curve which is given by the equation. please help. im trying to understand dc transients using this..
I started using Ltspice because most of the users here recommendded it.. now im trying to view the transient curve of a voltage of a capacitor when a dc voltage is applied..
for this i used a voltage source with a pulse of 5 volts and a 10 k resistor in series with a 1n capacitor.. but in the process of charging the capacitor the curve is a line instead of the exponential curve which is given by the equation. please help. im trying to understand dc transients using this..
hmm.. yeah i think i understand that.. in this configuration you've left the rise time as zero.. so you get the transient effect regardless of the rise time.. am i correct?
hmm.. yeah i think i understand that.. in this configuration you've left the rise time as zero.. so you get the transient effect regardless of the rise time.. am i correct?
hi,
As I have set the Stop Time at 100uS and Time Step at 1uS, LTS is smart enough to realise that a fast Rise/Fall time is required in order to give the required plot.
Why dont you experiment with different Rise/Fall times and see the effect.
Sorry it took me so long to post this, but here is what I thought you were trying to do:
I figured you wanted to hook a DC source (battery ) to your RC network, and then watch the capacitor charge. When doing a Transient solution (.TRAN), any Spice first does a DC solution to figure the operating point of the circuit before doing the transient solution. Unfortunately, that causes the capacitor to "precharge" to 10V, so when the transient solution
happens, the capacitor is already charged, so nothing happens but a "flat line".
To see the "charging" of the capacitor, it is necessary to suppress the default behavior by using the .IC V(out) = 0 statement, which forces the DC pre-solution to leave the capacitor uncharged, enabling you to see the transient as the capacitor charges through the resistor.