Signal Generator in Electronic Devices:
Colpitts Oscillator using Op Amp : The Colpitts Oscillator using Op Amp circuit show in Fig. 16-4 is similar to the op-amp phase shift oscillator, except that an LC network is used to produce the necessary phase shift in the feedback voltage. In this case, the LC network acts as a filter that passes the oscillating frequency and blocks all other frequencies. The filter circuit resonates at the required oscillating …
Crystal Equivalent Circuit : Crystal Equivalent Circuit – The output frequency of oscillator circuits is normally not as stable as required for a great many applications. The component values all have tolerances, so that the actual oscillating frequency may easily be 10% higher or lower than the desired frequency. However, by making a capacitor or resistor partially adjustable, the frequency of most oscillator circuits can be set fairly precisely. Such …
Hartley Oscillators using Op-Amp : Hartley Oscillators using Op-Amp circuit is similar to the Colpitts oscillator, except that the feedback network consists of two inductors and a capacitor instead of two capacitors and an inductor. Figure 16-7(a) shows the Hartley Oscillators using Op-Amp circuit, and Fig. 16-7(b) illustrates the fact that L1 and L2 may be wound on a single core so that there is mutual inductance (M) between the …
Oscillator Amplitude Stabilization Circuit : Output Amplitude – For all of the Oscillator Amplitude Stabilization Circuit discussed, the output voltage amplitude is determined by the amplifier maximum output swing. The output waveform may also be distorted by the amplifier output saturation limitations. To minimize distortion and reduce the output voltage to an acceptable level, amplitude stabilization circuitry must be employed. Oscillator Amplitude Stabilization Circuit operates by ensuring that oscillation is …
RC Phase Shift Oscillator Circuit Diagram : Figure 16-1 shows the RC Phase Shift Oscillator Circuit Diagram, which consists of an inverting amplifier and an RC phase-shifting network. The amplifier phase-shifts its input by -180°, and the RC phase-lead network phase-shifts the amplifier output by a +180°, giving a total loop phase shift of zero. The attenuated feedback signal (at the amplifier input) is amplified to reproduce the output. In …
Wein Bridge Oscillator using Op Amp : The Wein bridge is an ac bridge that balances only at a particular supply frequency. In the Wein Bridge Oscillator using Op Amp (Fig. 16-10), a Wein bridge circuit is used as a feedback network between the amplifier output and input. The bridge is made up of all of the resistors and capacitors. The operational amplifier together with resistors R3 and R4 constitute …