I need a circuit for modulating a control damper. I have a scrounged Honeywell damper control that is controlled by a 10 1/2 to 13 1/2 v. DC signal. I want to control it with a thermostat type circuit over a fairly small range....about 35 to 85 deg. F. I'm thinking maybe a thermistor based ckt. that would control a variable voltage regulator. Don't know how strong a signal it has to be, but from my experimentation, apparently it doesn't take much. I Put a 10k pot across a 13 1/2v. supply and drove it ok with a signal from the slider. The voltage regulator idea is probably overkill. Anybody have anything on hand or know where to find it? 120 vac will be available for power. Bob.