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Digital Electronics
Figure 4.53(a) shows a practical oscillator circuit. The frequency of oscillation in this case is given
by Equation (4.13) (the duty cycle of the waveform is approximately 50 %):
f = 1/2CC0405R eq + 0693R 1
(4.13)
where R eq = R 1 .R 2 /(R 1 + R 2 .
Figure 4.53(b) shows another circuit using two inverters instead of three inverters. The frequency
of oscillation of this circuit is given by the equation
f = 1/22RC
(4.14)
The circuits shown in Fig. 4.53 are not as sensitive to supply voltage variations as the one shown in
Fig. 4.52. Figure 4.54 shows yet another circuit that is configured around a single Schmitt inverter. The
capacitor charges (when the output is HIGH) and discharges (when the output is LOW) between the
Figure 4.53 Square-wave oscillator with external components.
Figure 4.54 Schmitt inverter based oscillator.
Digital Electronics
Figure 4.53(a) shows a practical oscillator circuit. The frequency of oscillation in this case is given
by Equation (4.13) (the duty cycle of the waveform is approximately 50 %):
f = 1/2CC0405R eq + 0693R 1
(4.13)
where R eq = R 1 .R 2 /(R 1 + R 2 .
Figure 4.53(b) shows another circuit using two inverters instead of three inverters. The frequency
of oscillation of this circuit is given by the equation
f = 1/22RC
(4.14)
The circuits shown in Fig. 4.53 are not as sensitive to supply voltage variations as the one shown in
Fig. 4.52. Figure 4.54 shows yet another circuit that is configured around a single Schmitt inverter. The
capacitor charges (when the output is HIGH) and discharges (when the output is LOW) between the
Figure 4.53 Square-wave oscillator with external components.
Figure 4.54 Schmitt inverter based oscillator.