The invention relates to a portable wide-limit high-stability 
constant current source. The portable wide-limit high-stability 
constant current source structurally comprises an ARM single-
chip microcomputer system, a touch screen module, a boosting module, a 
negative feedback amplifying module, a DA control module, a 
constant current source adjusting module, a 
current compensation module, a temperature measuring and keeping module, a sampling 
resistor module, a detecting module, a 
constant current source power supplying module, a power source module and other parts. The portable wide-limit high-stability 
constant current source can output high-precision 
voltage reference of any 
voltage value from 0 V to 10 V, the 
relative standard deviation of output 
voltage within a short time can reach 2.34*10<-7>, and the 
voltage stability is 3.4*10<-8>. The 
constant current source overcomes the defects that in a traditional constant 
current source adjusting tube 
voltage drop control circuit, a grade-
distribution transformer needs to be manufactured specially, sudden current change before and after switching is caused by uneven voltage grade distribution, a 
motor control circuit and a 
voltage regulator machinery speed reducing device are complex and huge, and after a 
switching power source is introduced, current stability and 
ripple waves are disturbed greatly.