Mike_Z
Newbie
I'm an old man, attempting to learn something new. Recently I read a little about Op Amps and wanted to try my hand at them. I purchased a breadboard, some parts, a Pico Scope and a power supply. My first circuit is a multi vibrator using a LM324. See attached diagram. The wave froms are of the capacitor voltage (triangular wave with the rounded tops), and the divider voltage (square wave). The other waveform is a calculation that the Pico can do. It is the divider voltage minus the capacitor voltage. I was trying to simulate the comparator of the LM324. My first question is, as the capacitor is charging through the 10k resistor, it will eventually equal the divider voltage. At this point in time the output of the LM324 should change from +Vsat to -Vsat. AND the capacitor should begin to discharge through the 10k resistor. If you inspect the attached JPG, the capacitor continues to charge for some time after the divider and capacitor voltages are the same. I thought maybe this was when the op amp was in it's linear part of operation, but I thought that the difference between the divider and cap voltages would only be about 1 milliVolt and not for as long as the diagram shows. I'd appreciate any help understanding what I'm looking at, Thank, Mike