Click Here to enter Utsource  site

IC Chips

74 series Digital Integrated Circuits

CD40 series Digital Integrated Circuits

Optical Couplers

Clock & Calculator ICs

Operational Amplifiers

Power Switch Ics

Driver Ics

Flash Memory

Memory

Audio Special Purpose

Clock/Timing - Application Specific

Clock/Timing - Clock Buffers, Drivers

Clock/Timing - Clock Generators, PLLs, Frequency Synthesizers

Clock/Timing - Delay Lines

Clock/Timing - IC Batteries

Clock/Timing - Programmable Timers and Oscillators

Clock/Timing - Real Time Clocks

Data Acquisition - ADCs/DACs - Special Purpose

Data Acquisition - Analog Front End (AFE)

Data Acquisition - Analog to Digital Converters (ADC)

Data Acquisition - Digital Potentiometers

Data Acquisition - Digital to Analog Converters (DAC)

Data Acquisition - Touch Screen Controllers

Embedded - CPLDs (Complex Programmable Logic Devices)

Embedded - DSP (Digital Signal Processors)

Embedded - FPGAs (Field Programmable Gate Array)

Embedded - FPGAs (Field Programmable Gate Array) with Microcontrollers

Embedded - Microcontroller, Microprocessor, FPGA Modules

Embedded - Microcontrollers

Embedded - Microcontrollers - Application Specific

Embedded - Microprocessors

Embedded - PLDs (Programmable Logic Device)

Embedded - System On Chip (SoC)

Interface - Analog Switches - Special Purpose

Interface - Analog Switches, Multiplexers, Demultiplexers

Interface - CODECs

Interface - Controllers

Interface - Direct Digital Synthesis (DDS)

Interface - Drivers, Receivers, Transceivers

Interface - Encoders, Decoders, Converters

Interface - Filters - Active

Interface - I/O Expanders

Interface - Modems - ICs and Modules

Interface - Modules

Interface - Sensor and Detector Interfaces

Interface - Sensor, Capacitive Touch

Interface - Serializers, Deserializers

Interface - Signal Buffers, Repeaters, Splitters

Interface - Signal Terminators

Interface - Specialized

Interface - Telecom

Interface - UARTs (Universal Asynchronous Receiver Transmitter)

Interface - Voice Record and Playback

Linear - Amplifiers - Audio

Linear - Amplifiers - Instrumentation, OP Amps, Buffer Amps

Linear - Amplifiers - Special Purpose

Linear - Amplifiers - Video Amps and Modules

Linear - Analog Multipliers, Dividers

Linear - Comparators

Linear - Video Processing

Logic - Buffers, Drivers, Receivers, Transceivers

Logic - Comparators

Logic - Counters, Dividers

Logic - FIFOs Memory

Logic - Flip Flops

Logic - Gates and Inverters

Logic - Gates and Inverters - Multi-Function, Configurable

Logic - Latches

Logic - Multivibrators

Logic - Parity Generators and Checkers

Logic - Shift Registers

Logic - Signal Switches, Multiplexers, Decoders

Logic - Specialty Logic

Logic - Translators, Level Shifters

Logic - Universal Bus Functions

Memory - Batteries

Memory - Configuration Proms for FPGAs

Memory - Controllers

PMIC - AC DC Converters, Offline Switchers

PMIC - Battery Chargers

PMIC - Battery Management

PMIC - Current Regulation/Management

PMIC - Display Drivers

PMIC - Energy Metering

PMIC - Full, Half-Bridge Drivers

PMIC - Gate Drivers

PMIC - Hot Swap Controllers

PMIC - Laser Drivers

PMIC - LED Drivers

PMIC - Lighting, Ballast Controllers

PMIC - Motor Drivers, Controllers

PMIC - OR Controllers, Ideal Diodes

PMIC - PFC (Power Factor Correction)

PMIC - Power Distribution Switches, Load Drivers

PMIC - Power Management - Specialized

PMIC - Power Over Ethernet (PoE) Controllers

PMIC - Power Supply Controllers, Monitors

PMIC - RMS to DC Converters

PMIC - Supervisors

PMIC - Thermal Management

PMIC - V/F and F/V Converters

PMIC - Voltage Reference

PMIC - Voltage Regulators - DC DC Switching Controllers

PMIC - Voltage Regulators - DC DC Switching Regulators

PMIC - Voltage Regulators - Linear

PMIC - Voltage Regulators - Linear + Switching

PMIC - Voltage Regulators - Linear Regulator Controllers

PMIC - Voltage Regulators - Special Purpose

Specialized ICs

Modules

IGBT

IPM

Thyristors

Rectifiers

Power Supply

Smart Power Module

SCR,GTO and Diode

FET

Darlington Transistors

RF Modules

CNC PRODUCTS

ENCODER

Motor

Servo drive & amplifier & Servo

Diode Module

Transistor Module

Switch Relay

PLC

Inverter

Contactor & Breaker

Elevator Board

Industry Control

Transistors

Diodes

Bipolar transistors

Resistors

Carbon Film Resistors

Cement Resistors

Chassis Mount Resistors

Chip Resistor - Surface Mount

Current Sense Resistors

Fusible Chip Resistor

High Precision & Low TCR SMD Resistors

High Voltage Resistor

LED Strip Resistors

MELF Resistor

Metal Alloy Resistors

Metal Film Resistor (TH)

Metal Glaze Resistors

Metal Oxide Film Resistors

Metal Oxide Resistors

NTC Thermistors

PTC Thermistors

Photoresistors

Potentiometers & Variable Resistors

Precision Potentiometer

Resistor Networks & Arrays

Resistor Networks & Arrays (TH)

Ultra Low Resistors (SMD)

Variable Resistors

Varistors

Wirewound Resistors

Capacitors

Aluminum Electrolytic Capacitors - SMD

CL21 Capacitor

Ceramic Disc Capacitors

High Voltage Capacitors

Metallized Polyester Film Capacitor

Multilayer Ceramic Capacitors MLCC - Leaded

Multilayer Ceramic Capacitors MLCC - SMD/SMT

Mylar Capacitor

Niobium Oxide Capacitors

Polyester Film Capacitors

Solid Polymer Electrolytic Capacitor

Supercapacitors & Ultracapacitors

Suppression Capacitors

Tantalum Capacitors

Trimmers, Variable Capacitors

Inductors & Ferrite Beads & Transformers

Antennas

Current Transformers

General Inductors (TH)

HF Inductors

Inductors (SMD)

LINE Filter

Power Inductors

Power Transformer

RJ45 Transformer

Radial Inductor (TH)

The circular inductors

Crystals

49S

49SMD

49U

Ceramic Resonators

DIP Oscillators(XO)

Radial Cylinder Crystals

SAW Resonators

SMD Crystals

SMD Oscillators(XO)

Connectors

AV Connectors

Audio & Video Connectors

Banana and Tip Connectors

Card Edge Connectors

Circular Connectors

Connector - Card Sockets

Connectors

Connectors - Accessories

Connectors - Housings

Contacts

D-Sub Connectors

Ethernet Connectors/Modular Connectors

FFC, FPC (Flat Flexible) Connectors

Fiber Optic Connectors

IC & Component Sockets

LED Light Pipes

Mezzanine Connectors (Board to Board)

PCB Connectors - Headers, Male Pins

PCB Connectors - Headers, Receptacles, Female Sockets

PCB Connectors - Housings

Power Connectors

RF Connectors/Coaxial Connectors

Shunts & Jumpers

Terminal Blocks - Accessories

Terminal Blocks - Barrier Blocks

Terminal Blocks - Din Rail, Channel

Terminal Blocks - Headers, Plugs and Sockets

Terminals

Test Clips

Test Points/Test Rings

USB Connectors

Unspecified Connectors

Screw-type wiring

Spring-type wiring

Pluggable Terminal Blocks

Through-wall Terminal Blocks

Automotive Terminals

Terminal Housings, Insulation Sleeves & Blocks

Quick Disconnect Wire Connectors and Terminals

Spare & Wear Tooling

Automotive Connectors

PCB Connectors

PC Laptop Parts

Lenovo Spare Parts

HP Spare Parts

Dell Spare Parts

Samsung Spare Parts

Asus Spare Parts

Microsoft Spare Parts

Huawei Spare Parts

Replacement Keyboards

Others

Laptop Screen

Mac Parts

LCD Screen

LCD Related Parts

Bottom Cover

Keyboard

Screws

Flex Cable

Touchpad

Power Board

Network Adapter

SSD Related Parts

Motherboard

Cooling Fan

Earpiece & Loundspeaker

Rubber Mats

Others

DJI Spare Parts

For DJI Phantom Series

For DJI Mavic Series

For DJI Spark Series

For DJI FPV Series

For DJI Mini Series

Others

iPhone 15 Pro Max Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Others

iPhone 15 Pro Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Others

iPhone 15 Plus Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Others

iPhone 15 Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Others

iPhone 14 Pro Max Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

FPC Connector

Others

iPhone 14 Pro Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

FPC Connector

Others

GoPro Spare Parts

Digital Camera Parts

Outer Screen

LCD Screen

Motherboard

Drive Board

Bayonet Mount Ring

Eyecups

Mode Dial

USB Cover Cap

Battery Cover

Flex Cable

Protective Leather

Card Slot

Button Cap

Shutter Blade Curtain

Others

iPhone 14 Plus Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

FPC Connector

Others

VR Spare Parts

iPhone 14 Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Others

iPhone 13 Pro Max Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Others

iPhone 13 Pro Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Others

iPhone 13 Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Others

iPhone 13 Mini Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Others

iPhone 12 Pro Max Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Side Key & Card Tray

Others

iPhone 12/12 Pro Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Metal Parts

Others

iPhone 12 Mini Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Metal Parts

Others

iPhone 11 Parts

Back Cover

LCD Related Parts

Flex Cable

Camera Series

Metal Parts

Others

iPhone 11 Pro Parts

Back Cover

LCD Related Parts

Flex Cable

Camera Series

Metal Parts

Others

iPhone 11 Pro Max Parts

Back Cover

LCD Related Parts

Flex Cable

Camera Series

Metal Parts

Others

iPhone XS Parts

Back Cover

LCD Related Parts

Flex Cable

Camera Series

Metal Parts

Others

iPhone XS Max Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Metal Parts

Others

iPhone XR Parts

LCD Related Parts

Back Cover

Flex Cable

Camera Series

Metal Parts

Others

iPhone X Parts

Back Cover

LCD Related Parts

Flex Cable

Camera Series

Metal Parts

Others

iPhone 8 Parts

LCD Screen

Glass Lens

Back Cover

Camera Series

Card Tray

Flex Cable

Metal Parts

Others

iPhone 8 Plus Parts

LCD Screen

Glass Lens

Back Cover

Camera Series

Button & Card Slots

Flex Cable

Metal Parts

Others

iPhone 7 Parts

LCD Screen

Glass Lens

Back Cover

Camera

Flex Cable

Metal Parts

Others

iPhone 7 Plus Parts

LCD Screen

Glass Lens

Back Cover

Camera

Flex Cable

Metal Parts

Others

Other iPhone Parts

iPhone 6S/6S Plus Parts

iPhone 6/6 Plus Parts

iPhone 5 Parts

iPhone 4/4S Parts

iPhone SE 2020 / 2022 Parts

SE 3rd Generation Parts

SE 2nd Generation Parts

SE 1st Generation Parts

iPad Pro Series Parts

12.9 inch

10.5 inch

9.7 inch

iPad Air Series Parts

iPad Air 2 Parts

iPad Air Parts

vivo Parts

LCD Screen

Outer Glass Lens

Touch Panel

Frame Bezel Plate

Back Cover

Flex Cable

Camera Parts

Charging Port Board

Single Tail Connector

Speaker Ringer Buzzer

Card Socket

Home key & Side Key

Others

iPad mini Series Parts

iPad mini 4 Parts

iPad mini 3 Parts

iPad mini 2 Parts

iPad mini Parts

OPPO Parts

LCD Screen

Outer Glass Lens

Touch Panel

Frame Bezel Plate

Back Cover

Camera Series

Flex Cable

Single Tail Connector

Speaker Ringer Buzzer

Card Socket

Home key & Side Key

Small Board

Others

Tecno Spare Parts

LCD Screen

Outer Glass Lens

Back Cover

Small Board

Single Tail Connector

Camera Parts

Flex Cable

Card Tray

Infinix Spare Parts

LCD Screen

Outer Glass Lens

Small Board

Single Tail Connector

Camera Parts

Flex Cable

Earpiece & Loundspeaker

Card Tray

itel Spare Parts

Alcatel Spare Parts

LCD Screen

Outer Glass Lens

Touch Panel

Back Cover

Flex Cable

Single Tail Connector

Small Board

Card Tray

OnePlus Parts

LCD Screen

LCD Related Parts

Frame Bezel Plate

Back Cover

Camera Series

Flex Cable

Tail Connector

Speaker Ringer Buzzer

Card Tray

Earpiece

Home key & Side Key

Adhesive Sticker

Others

Game Spare Parts

Switch Lite Spare Parts

Switch Spare Parts

PS5 Spare Parts

PS4 Spare Parts

NDS Spare Parts

3DS Spare Parts

Wii Spare Parts

PSP Spare Parts

PS3 Spare Parts

PS2 Spare Parts

XBOX Spare Parts

Steam Deck Spare Parts

Tools

iPad Series Parts

iPad 4 Parts

iPad 3 Parts

iPad 2 Parts

iPad Parts

Galaxy Spare Parts

LCD Screen

Touch Panel

Outer Glass Lens

Frame Bezel Plate

Back Cover

Camera

Card Socket

FPC Connector

Single Tail Connector

Charging Port Board

Wireless Charging Module

Home key & Side Key

Flex Cable

Earpiece & Loundspeaker

Vibrating Motor

Adhesive Sticker

Polarizing Film

OCA & LCD Backlight

Others

Huawei Spare Parts

LCD Screen

Touch Panel

Outer Glass Lens

Adhesive Sticker

OCA & Polarizing Films

Camera

Card Socket

FPC Connector

Tail Connector

Back Cover

Full Housing Cover

Flex Cable

Home key & Side Key

Fingerprint Ring

Earpiece & Loundspeaker

Earphone Jack

Others

Xiaomi Spare Parts

LCD Screen

Touch Panel

LCD Related Parts

Back Cover

Frame Bezel Plate

Backlight Plate & OCA

Camera

Tail Connector

Card Tray

Flex Cable

Speaker Ringer Buzzer

Earpiece Speaker

Vibrating Motor

Home key & Side Key

Adhesive Sticker

Others

Meizu Spare Parts

LCD Screen

Outer Glass Lens

Touch Panel

Frame Bezel Plate

Camera

Back Cover

Full Housing Cover

Tail Connector

Card Socket

Flex Cable

Home key & Side Key

Earpiece & Loundspeaker

Apple Serie Parts

Airpods Series

Apple Pencil Series

Batteries

For iPhone

For iPad & iPod Series

For Mac

For Samsung

For Xiaomi

For Huawei

For Sony

For LG

For Nokia

For Motorola

For Lenovo

For HTC

For OnePlus

For OPPO

For Watch

Others

Apple Watch Parts

LCD Related Parts

Back Cover

Flex Cable

Vibrating Motor

Middle Frame

Adhesive Sticker

Other Parts

Watch Spare Parts

For Samsung

For Huawei

For Xiaomi

For Fitbit

For Garmin

Other

Sony Spare Parts

LCD Screen

Touch Panel

Back Cover

Frame Bezel Plate

Flex Cable

Camera

LCD Backlight Plate

Tail Connector

Speaker Ringer Buzzer

Earpiece Speaker

Adhesive Sticker

Card Tray

Dust Plug

Others

HTC Spare Parts

LCD Screen

Touch Panel

Back Cover

Full Housing Cover

Camera Series

Tail Connector

Flex Cable

Speaker Ringer Buzzer

Adhesive Sticker

Others

Nokia Spare Parts

LCD Screen

Touch Panel

Outer Glass Lens

Replacement Keypad

Flex Cable

Back Cover

Adhesive Sticker

Full Housing Cover

Earpiece & Loundspeaker

Card Tray

Camera

Charging Port Connector

Charging Port Board

Lenovo Spare Parts

LCD Screen

Touch Panel

Outer Glass Lens

Tail Connector

Back Cover

Camera

Flex Cable

Others

Google Spare Parts

LCD Screen

Outer Glass Lens

Frame Bezel Plate

Back Cover

Flex Cable

Small Board

Camera Parts

Earpiece & Loundspeaker

Vibrating Motor

Card Tray

Adhesive Sticker

Others

ASUS Spare Parts

LCD Screen

Touch Panel

Outer Glass Lens

Camera

Tail Connector

Back Cover

Flex Cable

Speaker Ringer Buzzer

Frame Bezel Plate

Card Tray

Others

Microsoft Spare Parts

LCD Screen

LCD Related Parts

Flex Cable

Back Cover

Full Housing Cover

Camera Series

Others

Motorola Spare Parts

LCD Screen

Touch Panel

Outer Glass Lens

Frame Bezel Plate

Charging Port Board

Card Socket

Back Cover

Camera Accessories

Flex Cable

Earpiece & Loundspeaker

Others

More Brand Parts

For LG

For Amazon

For BlackBerry

For ZTE

For Acer

For BQ Aquaris

For Wiko

For Letv

For Vodafone

For 360

For CAT

For TCL

For T-Mobile

Others

iPod Parts

Touch Series

Other Parts

Shenzhen Brand Phone Parts

AGM

Doogee

LEAGOO

Blackview

Ulefone

UMIDIGI

Cubot

IIIF150

Others

IC Chipset

IC for iPhone

IC for Samsung

IC for Huawei

Power IC

Audio IC

Hard Disk for iPhone

Repair Tools

Screwdriver

Screwdriver Set

Tool Kits

Test Tools

Repair Fixture

Repair Programmer

Power Supply

Repair Glue Series

Adhesive Sticker

Laminator Machine

Separation Equipment

Laser Machines

Polishing Repair

Defoaming Equipment

Laminating Machines

Repair Platform

Crowbar

Brushes

Working Mat

Magnetic Screws Mat

Magnetizer Demagnetizer Tool

Sucker

Tweezers

Glove

Dust Remove Tool

BGA Stencils

Mould

Microscope Magnifier Series

Tool Boxes & Bags

Phone Film Cutter

Others

Sign In

3.Enter "account center"->"My inquiries" and check the status of your inquiries
liveTop

Dear customers, due to the implementation of the GDPR policy in Europe, UTSOURCE has also made adjustment accordingly to meet the policy requirements. Please read the new privacy policy carefully and this window will no longer pop up after you accept it.

I agree all UTSOURCE Terms & Conditions,Privacy Statement
Agree Later Submit

Delivery Address

Alternate Text

+ Add Address

Confirm

The new shipping address

*Country/Region :
*Contact :
*Cell Phone:
+

* Please fill in the cell phone number correctly to make sure that you can receive the tracking info in time.

Country Code
*Address :
*City :
Province/State :
*Province/State :
*Post Code :
Please enter a new 5-digit zip code..
Company :
Cancel
Submit

Building a Simple Audio Amplifier Using the 3SK45 FET

PViews:8

2024-11-26 17:39:56 source:Utsource author:
more information,enter the information center

In this DIY project, we will design and build a simple audio amplifier using the 3SK45 Field-Effect Transistor (FET). The 3SK45 is a N-channel JFET (Junction Field-Effect Transistor), commonly used for small-signal amplification due to its low noise and high input impedance characteristics. This makes it an ideal choice for building a high-quality audio amplifier that can be used in personal audio projects, such as headphone amplifiers, speaker amplifiers, or any project requiring low-power amplification.

The goal of this project is to create a single-stage audio amplifier that takes a weak audio signal (e.g., from a microphone or a musical instrument) and amplifies it to a level that can drive a speaker or be further processed. The circuit will utilize the 3SK45 as the main amplification component, taking advantage of its low noise and high input impedance to ensure a clear and distortion-free output.

By the end of this project, you'll have a basic understanding of transistor-based audio amplification, and you'll have built a functioning audio amplifier suitable for various DIY audio applications.

Key Components Used

3SK45 FET (Field-Effect Transistor)

The 3SK45 is an N-channel Junction Field-Effect Transistor (JFET) that is widely used for small-signal amplification. The JFET is known for its low noise and high input impedance, making it ideal for use in audio circuits, where preserving signal integrity is crucial.

Resistors

Resistors will be used to bias the transistor and set the gain of the amplifier. We will select values that ensure proper operation of the FET in its linear amplification region.

Capacitors

Capacitors are used for signal coupling and power supply decoupling. The coupling capacitors block any DC offset from the input and output signals, ensuring that only the AC audio signal is passed through the amplifier. Power decoupling capacitors will also help to filter out noise from the power supply.

Power Supply

The 3SK45 requires a suitable DC power supply, typically between 9V and 12V, which will provide the necessary voltage to power the amplifier. A regulated DC power supply is ideal for ensuring stable performance.

Potentiometer (Optional)

A potentiometer can be added to the circuit for volume control, allowing the user to adjust the amplification level.

Input/Output Connectors

Standard audio input (e.g., 3.5mm jack or RCA) and output connectors (e.g., speaker terminals or headphone jack) will be used to interface the amplifier with external audio sources and output devices.


Project Overview

This project involves building a simple single-stage audio amplifier using the 3SK45 FET. The circuit will take an audio signal as input, amplify it, and output a stronger audio signal that can drive a speaker or headphone.

The key features of this project include:

1. Single-stage amplification using the 3SK45 FET.

2. Volume control using a potentiometer (optional).

3. Coupling capacitors to pass only the AC audio signal.

4. Power decoupling to ensure clean operation.

5. Basic design that can be expanded for use in more complex audio systems.

The audio signal enters the circuit, passes through a coupling capacitor, and is amplified by the 3SK45 FET. The amplified output signal is then sent to the output device (such as a speaker or headphones) via another coupling capacitor to block any DC components.


Step-by-Step Build

1. Circuit Design

The design of the audio amplifier is based on the common-source amplifier configuration for the 3SK45 FET. This configuration is a standard approach for small-signal amplification, where the audio signal is fed into the gate of the FET, and the amplified signal is taken from the drain.

Basic Circuit Layout:

1. Input Capacitor (C1): The input signal is coupled to the gate of the 3SK45 through a coupling capacitor (C1). This capacitor ensures that only the AC audio signal is passed to the gate, blocking any DC offset that may be present in the input signal.

2. Biasing Resistors (R1, R2): These resistors form a voltage divider network that sets the proper bias voltage for the gate of the 3SK45 FET. The biasing ensures that the FET operates in its linear (active) region, where it can amplify the signal.

3. Source Resistor (R3): The resistor connected to the source of the FET helps stabilize the operating point of the transistor and sets the gain of the amplifier. The value of this resistor also impacts the overall linearity and performance of the amplifier.

4. Drain Resistor (R4): The resistor connected to the drain of the FET helps set the output impedance of the amplifier and works with the FET's characteristics to provide the desired amplification.

5. Output Capacitor (C2): The amplified signal is coupled to the output through a coupling capacitor (C2). This capacitor blocks any DC offset at the output and ensures that only the AC audio signal is passed to the next stage or to the speaker.

6. Power Supply Decoupling (C3): A small decoupling capacitor (C3) is used across the power supply to filter out any noise or ripple, ensuring that the amplifier operates cleanly.


2. Choosing Component Values

The component values are selected based on the operating characteristics of the 3SK45 FET and the desired performance of the amplifier. Here are some guidelines for selecting key components:

Biasing Resistors (R1, R2): The values of the biasing resistors depend on the desired gate voltage for the FET. The goal is to set the gate at a voltage that allows the FET to operate in the linear region. Typical values for R1 and R2 could be in the range of 10kΩ to 100kΩ, depending on the desired biasing.

Source Resistor (R3): The source resistor determines the gain of the amplifier. A typical value for R3 would be around 1kΩ to 10kΩ. A smaller resistor value gives higher gain, but too low of a value may result in distortion or reduced linearity.

Drain Resistor (R4): The drain resistor is responsible for setting the output impedance of the amplifier. A typical value might be in the range of 4.7kΩ to 10kΩ.

Coupling Capacitors (C1, C2): The values of the coupling capacitors depend on the input and output impedances of the circuit, as well as the frequency response. Capacitors in the range of 10µF to 100µF are commonly used for audio coupling.

Power Decoupling Capacitor (C3): A decoupling capacitor of 100nF to 1µF should be placed across the power supply to filter out any noise.


3. Building the Circuit

Now that we have our circuit design and component values, we can begin building the audio amplifier.

Power Supply:

1.Start by connecting the positive terminal of the 9V DC power supply to the drain of the 3SK45 FET through the drain resistor (R4).

2.Connect the ground of the power supply to the common ground of the circuit.

Biasing the FET:

1.Connect the gate of the 3SK45 to the input signal through the input coupling capacitor (C1).

2.Add the voltage divider network (R1 and R2) to provide the proper gate bias voltage.

Source Resistor:

1.Connect a resistor (R3) between the source of the 3SK45 and ground. This resistor helps set the operating point and gain of the amplifier.

Output Capacitor:

1.Connect the output coupling capacitor (C2) between the drain of the FET and the output terminal. The output signal will be taken from the drain, passing through this capacitor to remove any DC component.

Power Decoupling:

1.Place a small decoupling capacitor (C3) across the power supply to reduce noise and stabilize the voltage.

Volume Control (Optional):

1.If you want to add volume control to your amplifier, connect a potentiometer in series with the input signal to adjust the input level.


4. Testing the Circuit

Once the circuit is assembled, it’s time to test it.

Initial Power-Up:

1.Power the amplifier using a 9V DC battery or regulated power supply.

2.Check that the FET is correctly biased and that the amplifier is powered up.

Input Signal:

1.Apply a weak audio signal to the input. This could be a signal from an audio source like a smartphone, guitar, or microphone.

2.Monitor the output using headphones or a small speaker. The output should be an amplified version of the input signal.

Adjusting the Gain:

1.If the output is too loud or too quiet, adjust the potentiometer (if used) or change the source resistor (R3) to modify the gain.

Fine-Tuning:

1.Test with different audio frequencies (bass, treble, etc.) to ensure the amplifier works well across the audio spectrum.


5. Troubleshooting

If the amplifier isn’t working as expected, here are some troubleshooting tips:

1.Check the biasing: Make sure the biasing resistors are correctly sized to provide the appropriate gate voltage for the 3SK45.

2.Verify component connections: Double-check all connections, especially the input and output capacitors, as a misplaced connection can prevent the amplifier from working correctly.

3.Measure voltages: Use a multimeter to measure the voltages at key points (gate, drain, source) to ensure the FET is operating correctly.

4.Check power supply: Ensure that the power supply is providing a stable 9V to the circuit.


6. Conclusion

In this project, you’ve successfully built a simple audio amplifier using the 3SK45 FET. This amplifier can be used to amplify weak audio signals for various applications, including personal audio projects and small speaker systems.

The project has given you hands-on experience with basic JFET amplifiers, providing insight into biasing, signal coupling, and power decoupling. By fine-tuning the component values, you can modify the performance of this amplifier to suit different needs.

This DIY audio amplifier is a great starting point for anyone interested in learning more about analog audio circuits and can serve as the foundation for more complex audio systems in the future.

Key words: 3SK45

participate in discussions

New customer

Please login ? to participate in the comments

New customer Start here.

Submit

Comments

Toll-Free Call

(888) 766 5577 USA & Canada

+52 5515436027
+52 5515436028 Mexico

+49 6931090199 Germany

Whatsapp

+1 (657) 605-6198 USA

+49 15217848563 Germany

+52 55 7637 4368 Mexico

Email

sales@utsource.com

GLOBAL PAYMENTS

Global logistics

footShip
Copyright © 2022 Power by UTSOURCE HOLDING COMPANY LIMITED ISO/IEC 20000-1:2011,ISO/IEC 27001:2013 鄂ICP备2021003526号-1