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Showing posts from February, 2014

Small transistor amplifier Ideals

Currently, ICs has been used in many audio amplifiers,especially small circuit. It is convenient to use transistors.But when you need to use transistors, it has several advantages, such as saving you can take old equipment come to made small circuits easier than the IC. Which may be difficult to find. Take a look at these circuits. Maybe you get the idea of it.
Low impedance mini amplifier





This circuit can apply to signal sound source that has low impedance , such as from 4-16 ohm size loudspeakers or telephone earphone that use to replace , Micro phone. If use a loudspeaker replaces the rapidity will enough in sound checking that has been born from walking. The output this can feed reach input of high power amplifier the other next.


Power Amplifier OTL by AC176+AC126


Mr Somsak is my friend who like to make power amplifier so much. but he do not well electronic man. I so introduce he need make easy project before. This circuit is simple power amplifier OTL that mini watt output but is o…

Amplifier power supply using High Current Transformer

Circuit Description         Friends ever meet a problem power supply Circuit give current not enough. I has way this out give friends try apply. Follow this circuit High Current transformer parallel circuit make you have Current tall go up very. The transformer that have many the coil , we can bring to do high Current power supply circuit well. By if the all coil has Voltage be equal. It is can bring parallel can follow this circuit is coil lead that has Voltage 24V and have Current about 1A come to parallel prevent all 2 the group have current altogether each 2A groups by have voltage at 24V be the same. This circuit then can become Dual power supply at 34V positive and -34V Negative and Ground. This circuit uses to are amplifier power supply get good. Suppose will give the electric power about 50watt. For the diode use 3A 100V sizes and use. The Stancor for filter noise signal the all well. This circuit may help to give testimony have the idea in applying work other , get please sir…

100W subwoofer amplifier

General Description:      This is the circuit diagram of a fully transistorized sub woofer amplifier that can produce an output of 100W.There are seven transistors including four in the output stage. The transistors Q1 and Q2 form the preamplifier stage. Transistors Q4 to Q7 form the output stage. Since no ICs are used the circuit is very robust and can be easily assembled on a general purpose PCB.
Circuits features: The circuit can be powered from a +35V/-35V, 5A dual power supply.Use a 100W, 12 inch sub woofer at the output.All electrolytic capacitors must be rated 100V.The transistor Q4 to Q7 must be fitted with heat sinks.Circuit Diagram:


Dynamic microphone Amplifier for earphones

I decided to make this circuit so that I could listen to faint noises. It is a simple two-stage transistor amplifier design. The circuit was designed to use the input from a dynamic microphone but I am sure that with some modifications it would be possible to use an electret microphone. The 2N3053 transistors used in the design don’t have a particularly high gain so other types could probably be used as long as they are NPN.
source: eleccircuit.com


Computer Microphone

This circuit was submitted by Lazar Pancic from Yugoslavia. The sound card for a PC generally has a microphone input, speaker output and sometimes line inputs and outputs. The mic input is designed for dynamic microphones only in impedance range of 200 to 600 ohms. Lazar has adapted the sound card to use a common electret microphone using this circuit. He has made a composite amplifier using two transistors. The BC413B operates in common emitter to give a slight boost to the mic signal. This is followed by an emitter follower stage using the BC547C. This is necessary as the mic and circuit and battery will be some distance from the sound card, the low output impedance of the circuit and screened cable ensuring a clean signal with minimum noise pickup. original article soruse: eleccircuit.com

How to make 3V from one battery AA 1.5V

How to make 3V from one battery AA 1.5V






Telephone AmplifierLF351 and TBA820M

Amplifier description: This circuit TDA820M Mini Amplifier 2W+2W. Supply Volt 12V, Easy to build and Low cost. If you want mini amplifier circuit , as a result do not be defeated certainly. The sound will a little 2W+2W just but enough with 6 sizes are inch 8ohm loudspeakers. as a result still have a voice good loud the moderately. Request friends have fun the circuit amplifies this miniature please yes.

Circuit diagram:


PCB layout:

In Mono style a few parts and very cheap!
TBA820 mini AUDIO AMPLIFIER 1.2W
Here is Circuit Mini power amplifier low watt (1.2W Only). IN circuit have IC TBA820,it old IC Audio amp.

Low Power Wireless Audio Power Amplifier

Using this low-cost project one can reproduce audio from TV without disturbing others. It does not use any wire connection between TV and Loud Speaker. In place of a pair of wires, it uses invisible infra-red light to transmit audio signals from TV to Loud speakers, Without using any lens a range of up to 6 meters is possible. Range can be extended by using lenses and reflectors with IR sensors comprising transmitters and receivers.      IR transmitter uses two-stage transistor amplifier to drive two series-connected IR LEDs. An audio output transformer (T1) is used (in reverse) to couple audio output from TV to the IR transmitter. Transistors Q1 and Q2 amplify the audio signals received from TV through the audio transformer. Low impedance output windings (lower gauge or thicker wires) are used for connection to TV side while high-impedance windings are connected to IR transmitter. This IR transmitter can be powered from a 9V mains adapter or a 9V battery. Red LED (D1) in transm…

LM4910 Stereo Headphone Amplifier

Circuit description:
      LM4910 belonging to the Boomer series of National Semiconductors is an integrated stereo amplifier primarily intended for stereo headphone applications. The IC can be operated from 3.3V ans its can deliver 0.35mW output power into a 32 ohm load. The LM4910 has very low distortion ( less than 1%) and the shutdown current is less than 1uA. This low shut down current makes it suitable for battery operated applications. The IC is so designed that there is no need of the output coupling capacitors, half supply by-pass capacitors and bootstrap capacitors. Other features of the IC are turn ON/OFF click elimination, externally programmable gain etc.
Circuit diagram:
     Circuit diagram of the LM4910 stereo headphone amplifier is shown above.C1 and C2 are the input DC decoupling capacitors for the left and right input channels. R1 and R2 are the respective input resistors. R3 is the feed back resistor for left channel while R4 is the feed back resistor for the right …

Battery-powered Headphone Amplifier

Description:    Some lovers of High Fidelity headphone listening prefer the use of battery powered headphone amplifiers, not only for portable units but also for home "table" applications. This design is intended to fulfil their needs and its topology is derived from the Portable Headphone Amplifier featuring an NPN/PNP compound pair emitter follower output stage. An improved output driving capability is gained by making this a push-pull Class-B arrangement. Output power can reach 100mW RMS into a 16 Ohm load at 6V supply with low standing and mean current consumption, allowing long battery duration. The single voltage gain stage allows the easy implementation of a shunt-feedback circuitry giving excellent frequency stability.
     For a Stereo version of this circuit, all parts must be doubled except P1, SW1, J2 and B1.  Before setting quiescent current rotate the volume control P1 to the minimum, Trimmer R6 to maximum resistance and Trimmer R3 to about the middle of its tr…

Class-A Headphone Amplifier

This circuit is derived from the Portable Headphone Amplifier featuring an NPN/PNP compound pair emitter follower output stage. An improved output driving capability is gained by making this a push-pull Class-A arrangement. Output power can reach 427mW RMS into a 32 Ohm load at a fixed standing current of 100mA. The single voltage gain stage allows the easy implementation of a shunt-feedback circuitry giving excellent frequency stability.

     The above mentioned shunt-feedback configuration also allows the easy addition of frequency dependent networks in order to obtain an useful, unobtrusive, switchable Tilt control (optional). When SW1 is set in the first position a gentle, shelving bass lift and treble cut is obtained. The central position of SW1 allows a flat frequency response, whereas the third position of this switch enables a shelving treble lift and bass cut.      Before setting quiescent current rotate the volume control P1 to the minimum, Trimmer R6 to zero resistanc…

Mobile Car Stereo Player TDA1554

Using a mobile phone while driving is dangerous. It is also against the law. However, you can use your mobile phone as a powerful music player with the help of a stereo power amplifier. This does away with the need of a sophisticated in-dash car music system. Most mobile phones have a music player that offers a number of features including preset/manual sound equalisers. They have standard 3.5mm stereo sockets that allow music to be played through standard stereo headphones/sound amplifiers. Nokia 2700 classic is an example.


Mobile Car Stereo Player Circuit Diagram

     A car audio amplifier with 3.5mm socket can be designed and simply connected to the mobile phone output via a shielded cable with suitable connectors/jacks (readymade 3.5mm male-to-male connector cable is a good alternative). Fig. 1 shows the circuit of car stereo player. It is built around popular single-chip audio power amplifier TDA1554Q (IC1). The TDA1554Q is an integrated class-B power amplifier in a 17-lead …

Stereo Amplifier Circuit Diagram with TDA7052

BTL Stereo Amplifier Circuit Diagram with TDA7052

Amplifier Circuit 2W

Amplifier description:      This amplifier was designed to be self-contained in a small loudspeaker box. It can be feed by Walkman, Mini-Disc, iPod and CD players, computers and similar devices fitted with line or headphone output. Of course, in most cases you will have to make two boxes to obtain stereo. The circuit was deliberately designed using no ICs and in a rather old-fashioned manner in order to obtain good harmonic distortion behavior and to avoid hard to find components. The amplifier(s) can be conveniently supplied by a 12V wall plug-in adapter.Closing SW1 a bass-boost is provided but, at the same time, volume control must be increased to compensate for power loss at higher frequencies. In use, R9 should be carefully adjusted to provide minimal audible signal cross-over distortion consistent with minimal measured quiescent current consumption; a good compromise is to set the quiescent current at about 10-15 mA. To measure this current, wire a DC current meter temporarily in…

Mini Portable Guitar Amplifier

Guitar Circuit description:      This small amplifier was intended to be used in conjunction with an electric guitar to do some low power monitoring, mainly for practice, either via an incorporated small loudspeaker or headphones. The complete circuit, loudspeaker, batteries, input and output jacks can be encased in a small box having the dimensions of a packet of cigarettes, or it could be fitted also into a real packet of cigarettes like some ready-made units available on the market. This design can be used in three different ways: Loudspeaker amplifier: when powered by a 9V alkaline battery it can deliver about 1.5W peak output power to the incorporated loudspeaker.  Headphone amplifier or low power loudspeaker amplifier: when powered by a 3V battery (2x1.5V cells) it can drive any headphone set type at a satisfactory output power level or deliver to the incorporated loudspeaker about 60mW of output power. This configuration is useful for saving battery costs. Fuzz-box: when powere…

Crowbar Speaker Protection

Description Crowbar circuits are so-called because their operation is the equivalent of dropping a crowbar (large steel digging implement) across the terminals. It is only ever used as a last resort, and can only be used where the attached circuit is properly fused or incorporates other protective measures.
A crowbar circuit is potentially destructive - if the circuitry only has a minor fault, it will be a major fault by the time a crowbar has done its job. It is not uncommon for the crowbar circuit to be destroyed as well - the purpose is to protect the device(s) attached to the circuit - in this case, a loudspeaker.


There's really nothing to it. A resistor / capacitor circuit isolates the trigger circuit from normal AC signals. Should there be enough DC to activate the DIAC trigger, the cap is discharged into the gate of the TRIAC, which instantly turns on ... hard. A TRIAC has two basic states, on and off. The in-between state exists, but is so fast that it can be ignored for …

70 Watt Guitar Amplifier

Guitar Amplifier description:

Guitar Amplifier parts list: R1______________18K 1/4W Resistor
R2_______________3K9 1/4W Resistor R3,R6____________1K 1/4W Resistors R4_______________2K2 1/4W Resistor R5______________15K 1/4W Resistor R7______________22K 1/4W Resistor R8_____________330R 1/4W Resistor R9,R10__________10R 1/4W Resistors R11,R12_________47R 1/4W Resistors R13_____________10R 1W Resistor C1_______________1µF 63V Polyester Capacitor C2_____________470pF 63V Polystyrene or Ceramic Capacitor C3______________47µF 25V Electrolytic Capacitor C4______________15pF 63V Polystyrene or Ceramic Capacitor C5_____________220nF 100V Polyester Capacitor C6_____________100nF 63V Polyester Capacitor  D1,D2,D3,D4___1N4148 75V 150mA Diodes  Q1,Q2________BC560C 45V 100mA Low noise High gain PNP Transistors Q3,Q4________BC556 65V 100mA PNP Transistors Q5___________BC546 65V 100mA NPN Transistor Q6___________BD139 80V 1.5A NPN Transistor Q7___________BD140 80V 1.5A PN…

Mosfet Audio Amplifier 25W

General description: Can be directly connected to CD players, tuners and tape recorders. Simply add a 10K Log potentiometer (dual gang for stereo) and a switch to cope with the various sources you need. Q6 & Q7 must have a small U-shaped heatsink. Q8 & Q9 must be mounted on heatsink. Adjust R11 to set quiescent current at 100mA (best measured with an Avo-meter in series with Q8 Drain) with no input signal. A correct grounding is very important to eliminate hum and ground loops. Connect in the same point the ground sides of R1, R4, R9, C3 to C8. Connect C11 at output ground. Then connect separately the input and output grounds at power supply ground. Amplifier circuit diagram:

Part list:R1,R4 = 47K 1/4W Resistors
R2 = 4K7 1/4W Resistors
R3 = 1K5 1/4W Resistors
R5 = 390R 1/4W Resistors
R6 = 470R 1/4W Resistors
R7 = 33K 1/4W Resistors
R8 = 150K 1/4W Resistors
R9 = 15K 1/4W Resistors
R10 = 27R 1/4W Resistors
R11 = 500R 1/2W Trimmer Cermet
R12,R13,R16 = 10R 1/4W Resistors
R14,R15 = 220R 1/4W Re…

Low pass filter - Subwoofer

General description      The acoustic spectrum is extended by very low frequencies 20Iz and reaches as the 20000Iz in high frequencies. In the low frequencies is degraded the sense of direction. This reason us leads to the utilization speaker for the attribution of very low frequencies. The manufacture that to you we propose distinguishes these frequencies, in order to him we lead to the corresponding amplifier. The acoustic filters are met in various points in the sound systems. The knownest application they are the filters baxandal for regulating tone low and high frequencies and filters crossover where the acoustic region is separated in subareas, in order to it leads the corresponding loudspeakers. The application that to you we propose is a simple filter of region that limits the acoustic region (20-20000Hz) in the region 20-100Hz.

     With the manufacture that to you we propose you can make a active filter in order to you lead a loudspeaker of very low frequencies. With this yo…

Detail of subwoofer

Variations in the anatomy of a subwoofer dramatically changes their performance characteristics. An increase in voicecoil size coupled with a stronger cone material yields a higher power handling and increased output. By combining quality materials with Rockford’s proprietary acoustic technologies, our subwoofer lineup is sure to meet your system’s demands.



Basket - Also referred to as the frame or chassis, this is the skeletal system of the speaker. Here to keep everything in its place.
Spider - Second part of the speakers suspension, connects the cone and voice coil to the basket and controls the travel of the cone assembly.
Voice Coil - The brains of the operation, directing the force from the magnet to push or pull based on the applied electrical signal.
Surround - First part in the speakers suspension, attached to the cone to maintain the centering of the voice coil in the magnetic gap.
Cone - A.K.A the diaphragm, this is the voice of the speaker. Shape and material dramatically…

MAX98500 Amplifier circuit 1x2.2W

MAX98500 general description:
The MAX98500 is a high-efficiency Class D audio amplifier that features an integrated boost converter, to deliver a constant output power over a wide range of battery supply voltages. The boost converter operates at 2MHz, requiring only a small (2.2µH) external inductor and capacitor. The automatic level control has a battery tracking function that reduces the output swing as the supply voltage drops, preventing collapse of battery voltage. The amplifier has differential inputs and an internal fully differential design. The MAX98500 also features three gain settings (6dB, 15.5dB, and 20dB) that are selectable with a logic input. The MAX98500 is available in a small, 0.5mm pitch 16-bump WLP package (2.1mm x 2.1mm). It is specified over the extended -40°C to +85°C temperature range.
MAX98500 applications:
Active Speaker Accessories Cell Phones GPS Devices Mobile Internet Devices Smartphones Data Sheet
MAX98500 features:
Boosted Class D Output Integrated Autom…

LA3600 Equalizer 5 band

Applications:Portable component stereos, tape-recorders, radio-cassette recorders, car stereos.Features:On-chip one operational amplifier.5-band graphic equalizer for one channel can be formed easily by externally connecting capacitors and variable resistors which fix fo (resonance frequency).Series connection of two LA3600’s makes multiband (6 to 10 bands) available.Highly stable to capacitive load.LA3600 Circuit diagram:
LA3600 pcb: