Click the image to get the sch-rnd sheet
A notch filter built with two opamps: this filter passes signals between DC and 100 kHz but filters out 1 kHz signals. Demonstrated using a slotted opamp with simulation.
More info on the circuit: www.electronics-tutorials.ws
The lm358 contains two opamps in a single physical package. For the PCB workflow this is going to be a single footprint with 8 pins. For spice simulation, two separate components are exported, one per slot. The problem is: only slot 1's power terminals are connected! This is no problem for the PCB workflow, where a physical connection between slots exists within the package. For simulation, the trick is to set spice/shared on the power terminals on both slots (4 terminals total). This tells sch-rnd to share the connection between the same numbered terminals of different slots of the same symbol.
Other than this, everything else is pretty much the same as in 12_bjt_amp_ac.
Same as in 12_bjt_amp_ac.
Running ngspice the usual way on the export yields the following graphs:
Gnucap throws errors: open circuit: internal node ...
Gnucap uses a different command syntax. Modify the spice command symbol's spice/command attribute to:
print ac vdb(out) zp(out) op ac dec 10 1 1000k > plot.txt
After the export, write the single word spice in the first line of the file (e.g. using a text editor), otherwise gnucap won't know the file is in spice syntax. Then run gnucap 16_omapm_dc.cir and it will dump a text table to plot.txt that can be plotted using a suitable utility, e.g. gnuplot.
The gnucap-modified schematic is also available.
TODO