Linear Versus S.M.P.S.

Which is better?
Linear Power Supply using conventional 50/60 Hz. transformers or Switch mode power supply using active switching elements as main power components?

To answer this, let's break a major myth first. A properly designed S.M.P.S. produces lesser noise than the linear power supply. Reason to this lies in the fact that, linear supplies use big bulk capacitors ( higher capacitance) for filtering purposes contrary to smaller ones being used in S.M.P.S. Capacitors are a big source of noise and so is the linear power supply.

Low capacitance capacitors are used for S.M.P.S. for a simple reason that E.S.R. of the capacitor is dominant at S.M.P.S. working frequencies and hence is responsible for filtering than the actual capacitance value of the capacitor.

So next time onwards when you have to select a power supply for your application, give it a deep thought and of course I would be there to assit you in your selection.