Technical indicators of the DC power supply is divided into two types: one is the characteristic indexes, including allowing the input voltage and output voltage, output current and output voltage adjustment range; the other is a quality index, the degree of stability is used to measure the output DC voltage, including voltage coefficient (or voltage adjustment rate and output resistance (or) current, ripple voltage adjustment rate (around) and random drift) and temperature coefficient.
(1) ripple voltage: AC voltage component superimposed on the output voltage. Use the oscilloscope observation peak for MV magnitude. Can also be used AC voltmeter to measure its effective value, but because the ripple is not the sine wave, so there is a certain error, the general DC power supply ripple voltage VP-P = 10mV.
(2) voltage regulator: the relative change of the input voltage caused by the relative change in the input voltage and the ambient temperature.
(3): the relative change of voltage adjustment rate of output voltage is + 10% when the relative variation of the input voltage, voltage coefficient and voltage regulation are that the input voltage change of the output voltage, so one can only test.
(4) output resistance and current regulation
The output resistance of the output resistance and amplifier whose value is the same, when the input voltage is constant, the absolute value of the output voltage variation and output current variation ratio. Current adjustment rate: output current from 0 to the maximum relative change value of output voltage caused by. The output resistance and the current regulation rate all show the influence of the load current change on the output voltage, so it is necessary to test one of them.