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随着环境的日益恶化,自然不质得越来越差,即使是自来水难得靠得住。本文介绍一种日用水质检测仪,可将它放在厨房里,检测饮用水的水质,以保护自己的身体健康。 电路见图。220V交流电经变压器变压VD_1～VD_4整流、C_1滤被,获得+6V直流电源。VT_1和R_1、RP、探头AB组成电子开关。当AB两点间阻值较小时,VT_1的基极电压升高,VT_1导通并向后续电路输出电流。当A、B两点间阻值较大时,VT_1基极电位不降,VT_1截止,后续电路不工作。VT_2、VT_3、R_2和C_2组成互补振荡电路,当VT_1导通时,振荡电路工作,推动扬
With the worsening of the environment, nature is not getting worse and worse, even if tap water is rare and reliable. This article describes a daily water quality tester, it can be placed in the kitchen, drinking water quality testing to protect their own health. Circuit shown. 220V AC voltage transformer VD_1 ~ VD_4 rectification, C_1 filter was, get +6 V DC power supply. VT_1 and R_1, RP, the probe AB composed of electronic switch. When the resistance between two points AB is small, the base voltage of VT_1 rises, VT_1 turns on and outputs current to the subsequent circuit. When the A, B between the larger resistance, VT_1 base potential does not drop, VT_1 ends, the follow-up circuit does not work. VT_2, VT_3, R_2 and C_2 constitute a complementary oscillator circuit, when VT_1 is turned on, the oscillator circuit to promote the Young