window comparator

69 R. de Boer UBLI Iyu >Bá UL UH —Ui window comparator This window comparator uses only three CMOS inverters, two resistors, two preset potentiometers and one diode. Of course, the simplicity of the circuit means that some con- cessions must be made with regard to quality. High-frequency input signals with short rise and decay times cannot be properly proceseed. Nevertheless, the circuit provides an inexpensive and simple alternative to the usual window comparators. The circuit itself (figure 1) does not require much of a description. The switching thresholds are adjusted with preset potentiometers Pl and P2. The adjustment of Pl governs the lower switching threshold UL, whi lst that of P2 governs the upper switching threshold UH and thus establishes the window width UH — UL. Figure 2 clarifies the function of the circuit. The voltage values indicated apply to a supply voltage of 10 V. A triangular voltage is shown at the input of the window comparator, as well as the output...