Inside every VFD is a filament, grid ... [Fernando] built his circuit on a breadboard, and with a little tweaking managed to get a fairly respectable amount of gain from parts salvaged from ...

This build from [mircemk] is of the latter variety, repurposing a VFD display to do the job ... with an envelope follower circuit feeding a signal for the left and right channels into the analog ...

The work took place at West Jones High School with an assist participants in the 18th District Circuit Court ‘s Community ... units from Calhoun VFD arrived to find smoke visible from the ...