555 capacitance frequency transistor-line detector

  
As shown for the capacitor, the frequency detecting circuit transistor line. Can be converted by adjusting the preset switch K1 when this detector capacitance, frequency, trans
555 capacitance frequency transistor-line detector - schematic

istor testing. The K1 placed II detectable capacitance. 555 and R8 ~ R12 and measured capacitance Cx composition single stabilizing circuit, Cx capacity is increased, the pulse width, ie td 1.1 (R8 ~ R12) Cx longer, the greater the current average, indicating that the corresponding header greater. Circuit BG1 single junction transistor with R1, C3 composition relaxation oscillator, the oscillation output pulse signal as a trigger pulse of the IC. The K1 placed III frequency measurements can be carried out. At this one-shot circuit IC output td signal 1.1 (R8 ~ R12) CB fixed value width. The higher the frequency of the input signal. Frequency IC is triggered, the more the greater the average current, the greater the corresponding table header indicates. The K1 place I can be online test transistor. The principle is similar to the detection capacitor. Circuit transistor BG1 complete positive and negative power conversion. With IC output high and low alternating changes, if the light-emitting diodes LED1, LED2 turn light, then the transistor is good, otherwise the transistor is bad.




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