Breakdown is as follows:
I made the power supply of a multichannel output, besides main control loop, other way all uses 3 end manostat comes stabilized voltage. The power source power that I become is very little have 20 tile, every parameter is 5V/0.1A, 12V/0.4A, 24V0.4A, - 12V/0.1A, but do not know why even if in 5V/0.1A that is outputted all the way, 7805 very very hot also although added carbon fin to still be ironed quite, among them the input of 7805 carries voltage to be 12V. Illuminate learn manage to say should unapt so very hot ability checks so little power, can everybody give a dot the opinion.
Solve:
Sending very hot prime cause is quantity of heat comes loose not to go out, the specification is to exceed power:
1, it is power the design is insufficient
2, output short circuit
3, input voltage exceeds be restricted
Additional, hair is very hot also allow, should do not last only rise
According to I2R, have 0.5W, general of 7805 should use up 25% , 0.5/0.75-0.5=0.2W. General power is in 0.7w.
And the estimation of parts of an apparatus that TO220 encloses is controlled in 0.5W, although such, radiator also can be sent very hot, irrespective nevertheless, notice TO220 is enclosed add radiator the biggest namely 5W left and right sides.
Additional, 3 end have a stabilized voltage canal before interior of parts of an apparatus, if stabilized voltage provides the resistance in front,have a problem, the electric current that brings about input end is too big, temperature also can lift of course, if this kind of circumstance changes pipe