Band 2 Preamplifier
The described circuit employs a configuration of two Field Effect Transistors (FETs) to achieve enhanced amplification characteristics suitable for high-frequency applications. The lower FET, configured in common source mode, is responsible for providing voltage gain. This configuration is known for its ability to amplify small signals while maintaining a relatively high input impedance and low output impedance, which is advantageous for interfacing with other circuit stages.
In contrast, the upper FET is configured in common gate mode. This configuration is particularly effective for high-frequency applications as it offers a low input capacitance and high bandwidth. The common gate arrangement allows for improved stability and linearity, making it suitable for RF amplification. The combination of the common source and common gate configurations in a single circuit allows for a broad frequency response and high overall gain.
The tunability of the lower FET is a critical feature, as it enables the circuit to be adjusted for optimal performance at a specific frequency, such as that of a targeted radio station. This tunability can be achieved through the use of a variable resistor or capacitor in conjunction with the FET, allowing for fine-tuning of the gain characteristics and frequency response.
Coil details, which are essential for determining the resonant frequency and impedance matching of the circuit, would typically include specifications such as inductance, Q factor, and physical dimensions. These parameters will play a significant role in the overall performance of the circuit, particularly in tuning and frequency selectivity.
Overall, this circuit design exemplifies a sophisticated approach to high-frequency amplification, leveraging the unique properties of FETs in different configurations to achieve desired performance metrics. The integration of tunable components further enhances the versatility and functionality of the circuit in practical applications.The lower FET operates in common source mode, while the upper FET, operates in common gate, realising full high frequency gain. The bottom FET is tunable allowing a peak for a particular station. Coil details follow: 🔗 External reference
Related Circuits
This preamplifier features a built-in regeneration control that enhances gain selectivity. CI represents a single or multi-gang AM broadcast-band tuning capacitor, while LI is a ferrite loop antenna tapped at approximately 15 to 25% of the total turns. This...
A bandpass filter passes a range of frequencies while rejecting frequencies outside the upper and lower limits of the passband. The range of frequencies to be passed is called the passband and extends from a point below the center...
Most audio amplifier systems must have preamplifiers with many different characteristics. These include high-gain linear response for magnetic microphones, low-gain linear response for tuners, and high-gain RIAA equalization for magnetic phone cartridges. To meet this broad requirement, most amplifier...
A general-purpose preamplifier/mixer accepts up to four inputs, has a gain of 1600, and provides bass and treble controls that can be varied ± 10 dB at 100 Hz and 10 kHz respectively. More: IC1 and IC2 = LM301A. This...
This 10-band graphic equalizer circuit utilizes a single chip, the IC TL074, to create a 5-band graphic equalizer suitable for high-fidelity audio systems. The 5-band graphic equalizer is particularly effective for radio-cassette players and car stereos. Key features include...
CW is the simplest form of modulation. The output of the transmitter is switched on and off, typically to form the characters of the Morse code. CW transmitters are simple and inexpensive, and the transmitted CW signal doesn’t occupy...