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发表于 2009-4-16 13:48
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本帖最后由 lijingwei 于 2009-4-16 13:54 编辑
电压表的原理图:
R1 = 180k P1 = 20k trimmer multi turn
R2 = 22k U1 = ICL 7107
R3 = 12k LD1,2,3,4 = MAN 6960 common anode led displays
R4 = 1M
R5 = 470k
R6 = 560 Ohm
C1 = 100pF
C2, C6, C7 = 100nF
C3 = 47nF
C4 = 10nF
C5 = 220nF
0 - 2 V ............ R3 = 0 ohm 1%
0 - 20 V ........... R3 = 1.2 Kohm 1%
0 - 200 V .......... R3 = 12 Kohm 1%
0 - 2000 V ......... R3 = 120 Kohm 1%
这个是老外做过的,但是照他说的量程选择好像有点问题,这几天还没有忙得过来看看到底要怎么选择,发个源地址:
http://www.electronics-lab.com/projects/test/014/index.html
上面有PCB图和实物图。 |
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