Define turns ratio and its relationship with voltage transformation.
1 Answer
A Wien bridge oscillator is a type of electronic oscillator circuit that generates sinusoidal or sine wave signals at a specific frequency without the need for an external input. It was first proposed by Max Wien in 1891 and later improved by William Hewlett and Dave Packard, founders of Hewlett-Packard.
The basic Wien bridge oscillator circuit consists of a bridge network that balances two arms of the bridge at a particular frequency, creating positive feedback to sustain oscillations. Here's an explanation of how it operates:
The Wien Bridge Network: The Wien bridge oscillator circuit includes a bridge network made up of resistors (R1 and R2) and capacitors (C1 and C2). The network forms two arms: one with R1 and C1 in series and the other with R2 and C2 in series. The midpoint between R1 and C1 is connected to one end of R2 and C2, while the other end of R2 and C2 is connected to the ground.
Operational Amplifier (Op-Amp): An operational amplifier (Op-Amp) is a crucial component of the oscillator. The Op-Amp has both inverting and non-inverting inputs, as well as a high gain.
Positive Feedback: The Op-Amp is connected as a non-inverting amplifier, and its output is fed back to the bridge network. The output of the Op-Amp is connected to the junction between R1 and C1 through a feedback resistor (Rf). This creates positive feedback, which is necessary for oscillations to occur.
Frequency Determination: The frequency of oscillation is determined by the values of the resistors and capacitors in the bridge network. Specifically, the frequency of oscillation (f) can be calculated as follows:
f = 1 / (2 * Ļ * R * C)
Where R is the resistance in the arms of the bridge (R1 or R2), and C is the capacitance in the arms of the bridge (C1 or C2).
Initial Startup: When the circuit is powered on, the Op-Amp output begins to amplify the signal, and the bridge network will generate some small noise or disturbance. Due to the positive feedback, this disturbance gets amplified and continues to grow.
Frequency Selection: As the oscillations start, the frequency of the signal generated depends on the values of the resistors and capacitors in the bridge network. If the bridge network is balanced, meaning that the impedances in both arms of the bridge are equal, then the circuit will oscillate at its natural resonant frequency.
Amplitude Stabilization: The Wien bridge oscillator's amplitude tends to grow until it reaches the point where nonlinearities in the Op-Amp or other components limit the amplification. The non-linearity acts as a stabilizing mechanism, preventing the amplitude from exceeding a certain value.
Output: The output of the Wien bridge oscillator is taken from the Op-Amp's output, which provides a sinusoidal signal at the oscillation frequency.
It's important to note that practical implementations of the Wien bridge oscillator may include additional components for stabilization, amplitude control, and frequency tuning, but the basic operation and principles remain the same.
The basic Wien bridge oscillator circuit consists of a bridge network that balances two arms of the bridge at a particular frequency, creating positive feedback to sustain oscillations. Here's an explanation of how it operates:
The Wien Bridge Network: The Wien bridge oscillator circuit includes a bridge network made up of resistors (R1 and R2) and capacitors (C1 and C2). The network forms two arms: one with R1 and C1 in series and the other with R2 and C2 in series. The midpoint between R1 and C1 is connected to one end of R2 and C2, while the other end of R2 and C2 is connected to the ground.
Operational Amplifier (Op-Amp): An operational amplifier (Op-Amp) is a crucial component of the oscillator. The Op-Amp has both inverting and non-inverting inputs, as well as a high gain.
Positive Feedback: The Op-Amp is connected as a non-inverting amplifier, and its output is fed back to the bridge network. The output of the Op-Amp is connected to the junction between R1 and C1 through a feedback resistor (Rf). This creates positive feedback, which is necessary for oscillations to occur.
Frequency Determination: The frequency of oscillation is determined by the values of the resistors and capacitors in the bridge network. Specifically, the frequency of oscillation (f) can be calculated as follows:
f = 1 / (2 * Ļ * R * C)
Where R is the resistance in the arms of the bridge (R1 or R2), and C is the capacitance in the arms of the bridge (C1 or C2).
Initial Startup: When the circuit is powered on, the Op-Amp output begins to amplify the signal, and the bridge network will generate some small noise or disturbance. Due to the positive feedback, this disturbance gets amplified and continues to grow.
Frequency Selection: As the oscillations start, the frequency of the signal generated depends on the values of the resistors and capacitors in the bridge network. If the bridge network is balanced, meaning that the impedances in both arms of the bridge are equal, then the circuit will oscillate at its natural resonant frequency.
Amplitude Stabilization: The Wien bridge oscillator's amplitude tends to grow until it reaches the point where nonlinearities in the Op-Amp or other components limit the amplification. The non-linearity acts as a stabilizing mechanism, preventing the amplitude from exceeding a certain value.
Output: The output of the Wien bridge oscillator is taken from the Op-Amp's output, which provides a sinusoidal signal at the oscillation frequency.
It's important to note that practical implementations of the Wien bridge oscillator may include additional components for stabilization, amplitude control, and frequency tuning, but the basic operation and principles remain the same.