i am fairly new to kicad and simulating with ngspice but was successful with a few simple circuits. However i haven’t got sucessful results when simulating a simple lm7915 circuit:
You did not tell us what you have expected and what you got instead.
The 79xx and 78xx series voltage regulators are a class of approx. 1 A output current devices. Vout is to be expected at -15 V at normal operation in your circuit. Your load resistor R1 is 1 Ohm. The resulting current would be -15 A, not possible with a 7915.
Thank you for pointing a newbie in the right direction.
I was expecting -15V of course and the fault was the high load through the resistor. Just as you said. So i got a pretty high voltage drop.
I forgot to put “Meg” behind the 1.
So sorry for the somewhat dumb question.
Anyway is there a way to simulate (and “measure”) the voltage at non connected wires? So that the resistor wouldn’t be necessary in the first place?
A lot of voltage regulators also have a minimum output current. Which means that if your resistor is too high, the output voltage may rise.
When you’re setting up a new simulation, and you’re unsure about a lot of parameters, start by using values that would give the most reliable results. For an 7915 that would be between hundred Ohm and a few kilo Ohm.
