Pulse detector principle and circuit diagram

Test - lowercase jpg

Kaixin micro test

Industrial Router Crystal 3.2*2.5mm 3225 26M (26.000MHZ) 12PF 10PPM 20PPM 30PPM

Test probe P100-M3

Photocoupler

The pulse detector circuit is shown as shown. The detection circuit can determine whether the pulse width or the timing time ends at a certain time, and can be used for timing control or timing determination of the pulse width. As shown in the figure, the input pulse voltage Vin is applied to the output terminal via R5, and the rising edge of the pulse is differentiated by C1 and R1, and BG1 is amplified to form a narrow pulse to trigger the single stable circuit 555. The circuit is triggered by the input pulse and the output is output. The timing is a high level of 1.1R2C2(s), and BG2 is turned on during the timing, so that the output is zero regardless of the level of the original input Vin. After that BG2 is cut off, if the input pulse has returned to zero, the output is still zero; if the input pulse is still at high level, the output is also high, indicating that the input pulse width is greater than the timing 1.1R3C2.
The circuit has a wide detection range. R3 can take 1KΩ-100KΩ, C2 takes 1000μF or more, and can detect pulse width or timing pulse width from 1μs to tens of minutes.