Microphone Pre-Amplifier Based on LM358

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This is easy to construct microphone pre-amplifier project using compact electret condenser microphone. The pre-amplifier is important building block of many audio communication systems. Circuit has been built around Op-Amp LM358.

Power supply : 5 to 12 VDC @ 10 mA
Output: Gain Approx. 100
On-Board electret condenser microphone
Header connector for connecting of power supply input and audio output
Power-On LED indicator
Four mounting holes of 3.2 mm each
PCB dimensions 35 mm x 40 mm

 

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14W Stereo Audio Amplifier LM4730

14W STEREO AUDIO AMPLIFIER

14W Stereo audio power amplifier build around LM4730 IC. The LM4730 is stereo audio amplifier capable of delivering typical 14W per channel of continues average output power a 4 Ohms or 8 Ohms load with less than 10% THD+N from  20Hz to 20Khz frequency. Each amplifier has an independent smooth transition fade-in/out mute and a power conserving standby mode which can be controlled by onboard slide switches.

 The LM4730 has short circuit protection and thermal shutdown feature that is activated when the IC temperature exceeds 150 centigrade. The LM4730 also has under voltage lock out feature for click and pop free power off and on. Amplifier required proper heat sink.

Applications
  • Audio Amplifier for High End Stereo TVs
  • Audio Amplifier for Component Stereo
  • Audio Amplifier for Compact Stereo
  • Audio Amplifier for PC
  • Audio Amplifier for Self Powered Speakers
Specifications
  • Outout Power into 4 Ohms or 8 Ohms , 14W
  • THD+N  10%
  • THD+N at 1Khz with 2X1W into 8Ohms 0.02%
  • Mute Attenuation 85dB
  • Standby Current 3.5mA (+/- 17V)
  • Dual power supply – ±18 VDC
  • Less then 10% THD+N from 20 Hz – 20 KHz
  • Onboard slide switch for mute and standby mode
  • Terminal pins for connecting left and right audio signal inputs
  • Header connector for connecting Potentiometer (POT) for volume adjustment
  • Power Battery Terminal (PBT) for easy dual power supply and speakers connection
  • Power-On LED indicator

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12W Audio Amplifier Circuit Based On TDA2006

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Project is built around TDA2006 PENTAWATT package. TDA2006 provide high output current and has very low harmonic cross-over distortion. Further the device incorporate- rates an original (and patented) short circuit protection system comprising an arrangement for automatically limiting the dissipated power so as to keep the working point of the output transistors within their safe operating area. A conventional thermal shutdown system is also included. The TDA2006 is pin to pin equivalent to the TDA2030.

Specifications:

18V 2amps Single Supply
Power supply up to 18 VDC
Output power 12 W @ 4 Ω, 8 W @ 8 Ω
TDA2006 provides high output current
Has very low harmonic and cross-over distortion
Short circuit protection/Thermal shutdown system in IC
Terminal pins for connecting audio signal input
Header connector for connecting potentiometer (POT) for volume adjustment
Screw terminal connector for easy power supply input and speaker connection
Power-On LED indicator
Heatsink for IC
Four mounting holes of 3.2 mm each with nut and stud
PCB dimensions 51 mm x 63 mm

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Stereo Tape Head Pre-Amplifier Circuit

STEREO TAPE HEAD PRE-AMPLIFIER (1)

The circuit is built around a popular Sanyo’s stereo head preamp IC LA3161. Low electrical signals from the playback heads are fed to pins 1 and 8 of IC1 via DC decoupling capacitors, respectively. Components between pins 2 and 3 and pins 6 and 7 provide adequate equalization to the signals for a normal tape playback.
Specifications:

Power supply: 9 ~ 12 VDC @ 20 mA
Output power: upto 200 mW
Input Resistance – 100 KΩ (Typ), Load Resistance – 10 KΩ (Typ)
Low noise, good ripple rejection owing to the on-chip voltage regulator
Berg pins for connecting power supply, input and output
Power-On LED indicator
Four mounting holes of 3.2 mm each
PCB dimensions 49 mm x 38 mm


STEREO TAPE HEAD PRE-AMPLIFIER SCHEMATIC

STEREO TAPE HEAD PRE-AMPLIFIER (3)


PCB LAYOUT

STEREO TAPE HEAD PRE-AMPLIFIER (2)

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STEREO TAPE HEAD PRE-AMPLIFIER (1)

Audio Oscillator Generator Adjustable 115Hz-1Khz

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Audio Oscillator project simply produces audio tones for use in the range of 115 Hz to 1 KHz.  This kit is a must for audio technicians and experimenters alike.

Input : 6 VDC @ 325 mA
Output : Speaker, 8 Ω / 0.5 W
Range 115 Hz to 1 KHz Selectable by Onboard PRESET
ON/OFF slide switch for power supply
Terminal pins for supply voltage and speaker output
Power-On LED indicator
Four mounting holes of 3.2 mm each
PCB dimensions 39 mm x 42 mm

 

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2 Tone Audio Oscillator Circuit

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2 Tone Audio Oscillator is a simple circuit which will generate audio tone on the press of a button.  This circuit can be very useful as test equipment for audio equipment or as a signal source in an audio input.

Input – 5 ~ 12 VDC @ 100 mA
Output – Speaker, 8 Ω / 0.25 W
Two switches produce / play different frequencies
Frequencies 1.2 KHz, 700 Hz
Terminal pins for supply voltage
Power-On LED indicator
Four mounting holes of 3.2 mm each
PCB dimensions 47 mm x 46 mm

 

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3 Tone Audio Oscillator Circuit CD4001

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3 Tone Audio Oscillator is a simple circuit which will generate audio tone on the press of a button. This circuit can be very useful as a test equipment for audio equipment’s or as a signal source for  an audio input.

Input – 12 VDC @ 100 mA
Output – Speaker, 8 Ω / 0.25 W
Three switches produce 1.2 KHz, 725 Hz and 325 Hz
Terminal pins for supply Voltage and speaker connection
Power-On LED indicator
Four mounting holes of 3.2 mm each
PCB dimensions 42 mm x 48 mm

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3 Tone Musical Bell with Audio Amplifier

 3 TONE MUSICAL BELL

3 Tone Musical Bell project is built around BT66T (UM66) IC driving LM386 audio amplifier to give that extra punch.

 

  • Input 6 VDC @ 200 mA
  • Output 8 Ohms 0.5 W Speaker
  • Terminal pins for supply voltage and speaker connection
  • Power-On LED indicator
  • Onboard push to ON switch
  • Four mounting holes of 3.2 mm each
  • PCB dimensions 35 mm x 54 mm

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Light Sensitive Audio Oscillator

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Light Sensitive Audio Oscillator project is a fun loving project which will create different sound effects depending on the light falling on the sensor (LDR).

Features

  • Supply input 5 ~ 12 VDC
  • Output 8 Ohms, 0.5 W Speaker
  • Terminal pins for supply voltage and speaker connection
  • Power-On LED indicator
  • PCB dimensions 38 mm x 44 mm

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Water Level Sensor Alarm

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This small water sensor alarm circuit makes a loud warning sound when a water  sensor detects a quantity of water.

Features

  •  Input : 9 VDC @ 40 mA
  •  Output : Buzzer
  •  Berg connector for voltage supply input
  •  Power-On LED indicator
  •  Four mounting holes of 3.2 mm each
  •  PCB dimensions 35 mm x 32 mm

 

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