I would like to implement a 3 stage sample and hold circuit, but I want to take three discrete readings at about a 1 second interval, and then average the results. Is there an easy or effective way of doing this using only passive components? So far all I can think of is the use of 3 different RC timers triggering 3 different sample and hold circuits and then averaging the final result, but then capacitor leakage will affect the stored voltage, and there is a high component count.