From: jl@glen--canyon.com   
      
   On Fri, 13 Feb 2026 06:40:05 -0900, Christopher Howard   
    wrote:   
      
   >piglet  writes:   
   >   
   >> If high precision is not needed and only LF response is enough then I   
   >> have used PWM techniques:   
   >>   
   >> Circuit A is the basic squaring concept, relies on modern open-drain   
   >> output comparators being pretty good switches to ground. Assumes you   
   >> already have a source of sawtooth or triangle waves with defined zero   
   >> and peak values in the system.   
   >>   
   >   
   >Could you please explain better how the PWM squarer circuit works? It   
   >look like it would be easy to build, but I don't grasp what is going on.   
      
   A fairly simple single-opamp or comparator circuit can convert input V   
   to a duty cycle n. A transistor or analog switch or even a diode can   
   multiply V * n. Lowpass filter that and you have V^2.   
      
      
   John Larkin   
   Highland Tech Glen Canyon Design Center   
   Lunatic Fringe Electronics   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)