TDA1521 / TDA1521Q: 12W Stereo Amplifier

This is a stereo audio amplifier circuit that provides 12W output power on each audio channel. This simple circuit is built on a single integrated circuit of TDA1521 / TDA1521Q, and only supported by few external components.

TDA1521/TDA1521Q is a dual high-fidelity audio amplifier encapsulated in a plastic 9-leads. The device is specially designed for power supply applications (eg, stereo TV and radio). A heatsink is needed to prevent overheating the IC.

TDA1521/TDA1521Q features:

• Requires very few external components
• Low offset voltage between output and ground
• Input muted during power-on and off
• (no switch-on or switch-off clicks)
• Hi-fi according to IEC 268 and DIN 45500
• Excellent gain balance between channels
• Short-circuit-proof
• Thermally protected

This hi-fi stereo power amplifier is designed for mains fed applications. The circuit is designed for both symmetrical and asymmetrical power supply systems. An output power of 2 x 12 watts (THD = 0,5%) can be delivered into an 8 W load with a symmetrical power supply of ± 16 V.

Download the TDA1521/TDA1521Q Datasheet Here

Basic Monostable Multivibrator based IC 555

The following diagram is the circuit diagram of the very basic monostable multivibrator which built based on timer IC 555.

Parts list:
R1 = see notes
C1 = see notes
C2 = 10nF
IC1 = LM555

Notes:

• R1 and C1 determine length of output pulse where t=R1xC1 and R1 is in ohms and C1 is in farads.
• Pin 4 is the RESET. Leave it connected to power supply (+V) during normal operation. Bring pin 4 AND pin 2 low at the same time to reset timing cycle.

Portable Amplifier based on TEA2025

This is the diagram of simple portable amplifier circuit. This amplifier circuit build based on IC TEA2025 that is a monolithic integrated audio amplifier of 16-pin plastic dual in line package built by UTC manufacture. The circuit has an internal thermal protection. The circuit designed for portable cassette players and radios. You can also use as PC audio amplifier.

Here the amplifier diagram for stereo audio input/output:

and here the amplifier with mono audio input/output (bridge):

Stereo per channel
VCC=9V; RL=4 ohm/3W
VCC=9V; RL=8 ohm/2W

Bridge Application
VCC=9V; RL=8 ohm/5W
VCC=9V; RL=4 ohm/8W

Supply Voltage min = DC3v @ 500mA
Supply Voltage max = DC12v @ 500mA
Supply Voltage recommended = DC9v @500mA

Download TEA2025 Datasheet
Download the schematic diagram in PDF format HERE

2x22W Stereo Power Amplifier circuit based TDA1554

This is is a stereo power amplifier circuit works up to 22W on each channel. It will be 2x22W output. A few externel components required to support the main component of TDA1554. Heatsink on the power IC is a must to prevent overheating on the power IC. The chip should run cool enough to touch with the proper heatsink installed.

Component part list:

R1__________39K 1/4 Watt Resistor
C1,C2_______10uf 25V Electrolytic Capacitor
C3__________100uf 25V Electrolytic Capacitor
C4__________47uf 25V Electrolytic Capacitor
C5__________0.1uf 25V Ceramic Capacitor
C6__________2200uf 25V Electrolytic Capacitor
U1__________TDA1554 Two Channel Audio Amp Chip
MISC________Heatsink For U1, Binding Posts (For Output), RCA Jacks (For Input)

Operated at 12 Volts and at about 5 Amps at full volume. Lower volumes use less current, and therefore produce less heat. Printed circuit board is preferred, but universal solder or perf board will do. Keep lead length short.

LM3886 , 100W Power Audio Amplifier circuit

The following circuit diagram is the 100 Watt power audio amplifier circuit, build based on power amp chip LM3886. The single chip of IC LM3886 is able to amplify the audio power output up to 68W.

In this circuit, the two of LM3886 are paralled to gain more powerful amplifier output. This amplifier can deliver about 50W into a 8-ohm speaker and 100W into a 4-ohm speaker. To make a stereo amplifier, there are should be use 4 pieces of LM3886.

Circuit source: http://www.shine7.com/audio/pa100.htm

20W Bridge Car Amplifier based TDA7240A

The following circuit diagram is a bridge amplifier which specially designed for car audio system. The circuit is very simple with few external components supporting the power IC TDA7240A. This circuit will produce a maximum power output of 20W

Schematic Diagram:

PCB Layout:

The circuit diagram and PCB layout come from the IC TDA7240A datasheet. Download TDA7240A datasheet for circuit reference.

Positive Variable Power Supply circuit

The following diagram is the schematic diagram of positive adjustable/variable power supply. It means that the power supply output will be DC current with positive [+] and ground [0] polarity.

Schematic diagram:

Power Supply Input:

Component part list:
R1 = 330
R2 = 1K
VR1 = 10K 10-turn trimpot
C1 = 2200uF/50V
C2,4 = 100nF ceramic
C3,4 = 10uF/63V
D1-6 = 1N5403
REG IC = LM317T
Heatsink

Visit this page to download the variable power supply diagram manual.

32W HiFi Amplifier circuit based on TDA2050

This is a High Fidelify (Hi-Fi) amplifier circuit based on single IC TDA205. This is a mono channel audio amplifier. You need to build the same circuit for stereo channel.

Schematic diagram:

PCB Design:

TDA2050 Description:
The TDA 2050 is a monolithic integrated circuit in Pentawatt package, intended for use as an audio class AB audio amplifier. Thanks to its high power capability the TDA2050 is able to provide up to 35W true rms power into 4 ohm load @ THD =10%, VS = ±18V, f = 1KHz and up to 32W into 8ohm load @ THD = 10%, VS = ±22V, f = 1KHz. Moreover, the TDA 2050 delivers typically 50W music power into 4 ohm load over 1 sec at VS=22.5V, f = 1KHz.

The high power and very low harmonic and crossover distortion (THD = 0.05% typ, @ VS = ±22V, PO = 0.1 to 15W, RL=8ohm, f = 100Hz to 15KHz) make the device most suitable for both HiFi and high class TV sets.

Download TDA2050 datasheet for the circuit reference.