[sdiy] super simple portamento / slide / glide / slew limitingcircuit?

[David G Dixon]

> That'd be an integrator, like this:
> 
> http://www.electronics-tutorials.ws/opamp/opamp_6.html
> 
> Stick the cap in the feedback loop of an op-amp, use the 
> resistor to alter the current flowing into the cap. Since 
> it's inverting, you probably need a second op-amp and a 
> couple more resistors to reinvert, but it's still just one 8 pin DIP.

The problem with a simple integrator is that the ramp doesn't stop at the
input voltage, but continues on to the rail.  To stop the ramp, you need
something like the Bissell MorphLag.  This involves three opamps -- still
just a 14-pin dip.  You can use the spare opamp to provide a proper CV
follower off of the integrator to eliminate the small CV error from the
output resistor while providing proper capacitive load protection.  Email me
privately for details.