> Attached file as you can see its a small and simple psu. > this device produce heat to much, it only supply to a opamp about 10-15mA . > the regulators are very hot as well the input capacitors. You are trying to make a +- 9V regulated supply. The transformer secondaries are too high voltage for this, which will cause unnecessary heating in the linear regulators. The unregulated voltages will be 18 * sqrt(2) = 25V, possibly higher depending on input line voltage and what load the 18V is specified at. 25 - 9 = 16 volts drop on each regulator. 16V * 15mA = 240mW. That should cause noticeable heating in a TO-5 package, but should still be within tolerance. It should certainly not be "very hot", so something else is going on. The capacitors shouldn't be dissipating any power. They are either being heated indirectly by the regulators, or something is very seriously wrong. Are you sure the capacitors are installed the right way? If not they will draw excessive current, get hot, and explode in a minute or so. I'm serious about this. Don't put your face near this circuit if there is a chance the capacitors are installed backwards. They are drawn correctly on the schematic. Are you sure the load only draws 15mA? Is that what it's supposed to draw or what you've actually measured? ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body