Rangkaian Alat Bantu Pendengaran

This circuit, connected to 32 Ohm impedance mini-earphones, can detect very remote sounds. Useful for theatre, cinema and lecture goers: every word will be clearly heard. You can also listen to your television set at a very low volume, avoiding to bother relatives and neighbors. Even if you have a faultless hearing, you may discover unexpected sounds using this device: a remote bird twittering will seem very close to you.

Skema Rangkaian Alat Bantu Pendengaran

The heart of the circuit is a constant-volume control amplifier. All the signals picked-up by the microphone are amplified at a constant level of about 1 Volt peak to peak. In this manner very low amplitude audio signals are highly amplified and high amplitude ones are limited. This operation is accomplished by Q3, modifying the bias of Q1 (hence its AC gain) by means of R2.
A noteworthy feature of this circuit is 1.5V battery operation.

List Component

P1        : 22K   Log. Potentiometer
R1,R9     : 10K
R2        : 1M
R3        : 4K7
R4,R7     : 100K
R5        : 3K9
R6        : 1K5
R8        : 100R
C1,C2     : 100nF
C3,C6     : 1µF/63V
C4        : 10µF/25V
C5        : 470µF/25V
D1        : 1N4148
Q1,Q2,Q3  : BC547
Q4        : BC337
MIC1      : electret microphone
SW1       : SPST Switch
J1        : Stereo 3mm. Jack socket
B1        : 1.5V Battery (AA or AAA cell etc.)

Circuit from: www.sound.westhost.com

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Microphone Condenser Pre Amplifier Circuit

This is a simple preamplifier circuit for electret condenser microphone. using a LM1458 dual op amp IC. The circuit takes the audio signal rom the condenser microphone and amplifier it, so you can use the microphone as the input to some device which wouldn’t normally accept microphone level signals .

Schematic Circuit of Microphone Electret
Condenser Pre Amplifier

The circuit requires a 6-9 volt supply. Output of the microphone amplifier can be made variable by connecting a 10kΩ potentiometer . Circuit’s gain can be increased by men perbesar the value of 47K, depending on the input sensitivity of the main amplifier system. The microphone should be housed in a small round enclosure.

List componet of condenser pre-amp mic circuit

Q1,Q2    : LM1458 Op-Amp
R1,R2,R3 : 4.7k ohm resistor
R4, R5   : 10k ohm resistor
R6,R7    : 47k ohm resistor
C1,      : 0.22uF ceramic capacitor
C2       : 1uF ceramic capacitor

Absolute maximum ratings of LM 1458 IC

Supply Voltage               :  ±18V
Power Dissipation            : 400 mW
Differential Input Voltage   : ±30V
Input Voltage                : ±15V  
Output Short-Circuit Duration: Continuous
Operating Temperature Range  : 0°C to +70°C
Storage Temperature Range    : −65°C to +150°C
Lead Temperature             :(Soldering, 10 sec.) 260°C

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Rangkaian Audio Mixer 6 Channel

Audio Mixer 6 Channel

The following is a main of the mixer-6 Ch circuit. The circuit constituted by six input channels. The channels are from monophonic channels CH 1-4 and CH 5-6, are intended for stereo use. The number of input channels they want as long Itself Can Increase You Want.

Skema rangaian audio mixer 6 channel

The output of Each channel drives the RV1-6, that regulation potesometer level of sound. With RV7-12 We create conditions of balance Between two channels (BALANCE). All the signals from the input channels in this point are added by two adders [IC1a-b], for Each channel Here exist two Trimmer TR1-2 That adjust the gain of Each IC, adapting the level of signal of the output, in the level That We Want. They Can be suppressed if you do not need something and Standard and Poor. The next stage is a equalizer, three bands of regulation. The IC3α-b, constitute the output of the mixer, they want a one acre have gain and they want the make the essential isolation of the previous stages, with the unit That We Will drives. For whoever they want want they want use headphones, it exists a classic circuit drive of headphones, round the IC2a-b, that give the output in the JF13. It Can Also Also exist optical clue of audio levels, with a stereo VUMETER.

List component

• R1-12=4.7Kohms
• R13-24=10Kohms
• R25-26=22Kohms .
• R27-30-34-39=100ohms
• R28-29-36-37=100Kohms
• R31-42=10Kohms
• R32-41=4.7Kohms
• R33-40=10Kohms
• R35-38=47ohms
• RV1....4=47Kohms Log.
• RV5-6-13=2X47Kohms Log.
• RV7....12=10Kohms Lin. pot. Log
• C1....8=10uF 25V
• C9-11=47pF ceramic or mylar
• C10-12=47uF 25V
• C13-14=100uF 25V
• C15-16=2.2uF 16V
• C18-21=100pF ceramic or mylar
• C19-20=220uF 25V
• TR1-2=4.7Kohms trimmer
• Q1-3=BD139
• Q2-4=BD140
• IC2=NE5532 - TL072

All the Resistors is 1/4W 1% metal film C18-21=100pF ceramic or mylar

for more detail read here

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Rangkaian Op-Amp (LM741) Pre-Amp Mic

Op-Amp Pre-Amp Mic

This is the circuit of Op-Amp Microphone Preamplifier using a single power supply, this circuit suitable for dynamic or electret microphones. Nothing too special here. The Schematic is shown using a dynamic microphone, for use with an electret a pair of suitable biasing resistor is required to power the electret microphone.

Skema rangkaian op-amp pre-amp mic

Note:

• use a capacitor with voltage 25volt or more
• so that the sound produced maximal use supplay good voltage, with output of 18 volts max
• If the desired strengthening of the different, you can change the value of R1 or R2

The design is a standard non-inverting design, the input is applied to the non-inverting input of the op-amp, which is pin 3 in most cases. The input impedance is 23.5k, the overall voltage gain is determined by R2 and R1according to the following formula:

Vo = (R2 / R1) + 1

With the values of R2 and R1 on the diagram of the voltage gain (for mid band, 1kHz) is approximately 23x or 27.2dB.

Pinning IC Op-Amp LM741

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Microphone Komputer

Microphone Komputer

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.

Skema rangkaian microphone komputer

Transistor BC413B operates in common emitter to give a slight boost to the mic signal. This is followed by an emitter follower stage using transistor 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.

Transistor BC413

• Collector Emitter Voltage VCEO 30 V
• Collector Base Voltage VCBO 45 V
• Emitter Base Voltage VEBO 5.0 V
• Collector Current Continuous IC 100 mA
• Power Dissipation at Ta=25ºC PD 350 Mw Derate Above 25ºC 2.8 mW/ºC
• Power Dissipation at Tc=25ºC PD 1.0 W Derate Above 25ºC 8.0 mW/ºC
• Operating and Storage Junction TJ, Tstg ºC - 55 to +150

Transistor BC547C

• Collector-Base Voltage VCBO (IE = 0) 50 V
• Collector-Emitter Voltage VCEO (IB = 0) 45 V
• Emitter-Base Voltage VEBO (IC = 0) 6 V
• Collector Current IC 100 mA
• Collector Peak Current ICM 200 mA
• Total Dissipation at Ptot TC = 25 oC 500 mW
• Storage Temperature Tstg -65 to 150 oC
• Operating Junction Temperature Tj Max. 150 oC

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Rangkaian Pre-Amp Mic Condenser

Pre-Amp Mic Condenser

Microphone amplifier circuit is simple, consisting of 2 levels. with wide dynamic regions, small noise, and can with a long cable about 50 meters.

Skema rangkaian Pre-Amp mic condenser

Note:

all capacitor (elco) using 25-volt
to avoid the buzzing sound, use a good regulator supplay
This circuit can provide voltage 6-20volt

This circuit uses low noise transistors are type types: BC 650 C but the transistor is hard to find, so you can replace it with 109 BC is no less good. This condenser mic element in it is a very sensitive microphone, and to use this mic condenser required voltage between 2-10 volts, for that we can resistors in series with 1K-10 K ohms, in the picture above the tide 1k ohms

Pin BC109

1. Emitter
2. Base
3. ollector, connected to the case

BC109 limiting values

collector-base voltage 30 V
collector-emitter voltage 20 V
emitter-base voltage 5 V
collector current (DC) 100 mA
peak collector current 200 mA
peak base current 200 mA
total power dissipation Tamb £ 25 °C - 300 mW
storage temperature 65 +150 °C
junction temperature 175 °C
operating ambient temperature -65 +150 °C
DC current gain (hFE) IC = 10 mA; VCE = 5 V 100 -- 270

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Rangkaian Pre-Amp Mic 2 Transistor.

Here is a Pre-amp microphone dynamic using two transistors. The circuit factor of this around 150 and can handle signals from 50Hz to 100Khz.This circuit is designed for use with 200 Ohm dynamic microphones. For usage with low impedance microphones, the value of R3 must be increased to around 47o Ohms and C1 must be decreased to around 2.2uF.

Skema rangkaian Pre-Amp mic 2 transistor

The audio signal from the microphone is coupled to the base of Q1 via the capacitor C1 and resistor R3. Q1 works as a preamplifier here. The preamplified signal will be coupled to the base of Q2 for further amplification. Resistor network comprising of R4, R5 and R6 provides the necessary negative feedback. Final output signal will be available at the emitter of Q2.

Layout Transistor BC549 & BC546

Transistor BC549 Absolute maximum rating

• VCBO collector-base voltage open emitter...............30 V.
• VCEO collector-emitter voltage open base...............30 V.
• VEBO emitter-base voltage open collector................5 V.
• IC collector current (DC)........................................100 mA.
• ICM peak collector current......................................200 mA.
• IBM peak base current............................................200 mA.
• Ptot total power dissipation Tamb £ 25 °C..................500 mW.
• Tstg storage temperature...................................... -65 to +150 °C.
• Tj junction temperature..........................................150 °C.
• Tamb ambient temperature..................................... -65 to +150 °C.
• hFE DC current gain VCE = 5 V, IC = 2 mA .............420 to 800.

Transistor BC546 Absolute maximum rating

• VCBO collector-base voltage open emitter..................80 V.
• VCEO collector-emitter voltage open base..................65 V.
• VEBO emitter-base voltage open collector..................6 V.
• IC collector current (DC).........................................100 mA.
• ICM peak collector current.......................................200 mA.
• IBM peak base current.............................................200 mA.
• Ptot total power dissipation Tamb £ 25 °C.................. 500 mW.
• Tstg storage temperature........................................ -65 +150 °C.
• Tj junction temperature...........................................150 °C.
• Tamb operating ambient temperature ........................-65 +150 °C.
• hFE DC current gain VCE = 5 V, IC = 10 mA..............150.

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Hifi stereo pre-amp head

This is hifi stereo pre-amp head with tone control circuit Using a special IC TDA1524A
All signal processing is done within the TDA1524A by voltage controlled amplifiers and voltage controlled filters. The IC provides a fixed voltage (~ 3.8V DC) at pin 17, and this is used by all the variable resistors to provide an adjustable DC voltage to the appropriate control pins.

Current sensing is used to provide a flat response when R5 is connected to pin 17, and a loudness contour when disconnected. 100 nF capacitors are used on each pot to decouple any AC signals from the control inputs. 10 uF capacitors are used to couple both input and output audio signals whilst blocking DC. R1 and R2, are to ensure stability with capacitive loads. R3 and R4 make sure there are no DC spikes at the output sockets if the load is switched. C3 and C4 control the loudness contour. C5 and C6 control the treble turn-over frequency. C18 and C19 have been added to roll off the gain above 70 kHz. Low volume settings coupled with treble boost was causing HF instability in some instances. This should no longer be a problem.

Skema rangkaian hifi stereo pre-amp head

C15, 16, 17 provide power supply filtering. D1 provides protection in case of incorrect supply polarity. The LED is a power on indicator and may be omitted if not required, or preferably mounted on the enclosure. If you are not using a switch pot, you can connect an external switch across the P1 switch pins, or connect a wire link there and switch the power supply.

The power supply is critical to the noise performance of the pre-amp head. An on board regulator is provided to reduce mains hum. If you wish to use it with a car or other 12V battery, then you should omit the 7812 regulator, and place a wire link between the regulator input and output pin positions on the PC board. Do not short to earth! This will be necessary because the regulator must have an input voltage at least 2-3V greater than it’s output, for it to maintain regulation. However the regulator will not be necessary with a battery supply.

If using a plug pack, it’s output voltage should be 15 to 18V DC. Because most plug packs have poor regulation, one rated at 12V DC will often be around 15V when lightly loaded. The current drain of the pre-amp is less than 50 mA, so many 12 V unregulated supplies may be adequate if you have one. Replace D1 with a wire link if necessary, making sure you have the supply polarity correct!

If you are using a 15-20V supply for your power amplifier, you can use that as your pre-amp supply as well. Make sure you test the voltage first in all cases.

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Rangkaian Pre- Amp mic 3 input - lm741

This is a 3 input mic mixer circuit using IC LM 741. Four 741s are used here. IC1, IC2, IC3 are used as preamplifiers. They produce a gain of around 40 decibel to the individual input signals. IC4 is wired as a summing amplifier to add the signals from three preamplifiers.IC4 also gives a gain of around 5 decibel to the final output signal. Total gain of the system is around 45 decibel.

Skema Rangkaian Pre- Amp mic 3 input

Note:
• Use+15/-15 V DC dual power for powering this circuit.
• All inputs and output must be connected with respect to the ground.
• Capacitors C1, C2 and C3 must be rated 10V and other capacitors must be 30V.


General Description

Lay out IC LM 741

The LM741 series are general purpose operational amplifiers which feature improved performance over industry standards like the LM709. They are direct, plug-in replacements for the 709C, LM201, MC1439 and 748 in most applications. The amplifiers offer many features which make their application nearly foolproof: overload protection on the input and output, no latch-up when the common mode range is exceeded, as well as freedom from oscillations. The LM741C is identical to the LM741/LM741A except that the LM741C has their performance guaranteed over a 0°C to +70°C temperature range, instead of −55°C to +125°C.

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Rangkaian Microphone/Mic FM Wireless

Microphone/Mic FM Wireless is basically an FM transmitter to low power. FM Wireless Mic circuit you can use it to replace the wireless mic is usually quite expensive price. If you are a fan of electronics, then the series is worth your trying, but its component prices cheaper tool is also very useful. Here is a picture of his series:

Skema Rangkaian Microphone/Mic FM Wireless

List Component of Microphone/Mic Wireless

1 = 10K (brown-black-orange)
R2,R3 = 100K (brown-black-yellow)
R4 = 470 ohm (yellow-violet-brown)
C1,C3 = 4.7pF (4p7), ceramic
C2,C4 = 4.7uF-16V, electrolytic
C5 = 0.001uF (1nF), ceramic
C6 = 470pF, ceramic
Q1,Q2 = 2N2222, NPN transistor
L1 = 1uH, variable inductor
Mic = Electret mike, 2 wires

Q1 amplifies the input signal via C4 from the electret microphone. Q2 acts as an oscillator and the signal coming off C2 is fed onto the base of Q2. L1/C1 is a so called ‘tank’ circuit and operates in the 88-105MHz band on your regular AM/FM radio dial.
L1 is a 1uH variable inductor coil to be able to tune it a little bit, and the range of 1uH is approximate. The antenna can be as simple as a 8″ (21cm) piece of wire of any kind.

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Rangkaian Audio Mixer 3 Input

Many audio mixer circuits have been published but this this very simple audio mixer circuit uses only one transistor. The base emitter junction of the transistor is biased by the diodes D1 and D2.The signals to be mixed are directly coupled to the base of Transistor. Each input lines are current limited by using a 10k Potensiometer . With the used component values the collector current is around 1mA.

Skema Rangkaian Audio Mixer 3 Input

Notice:

• The circuit can be assembled on a Vero board.
• The circuit can be powered from 9-25V DC.
• of each channel can be set using Variable resistor 10k

Transistors in the following series is enabled as a source of constant flow. By providing input audio signal on the emitter, the voltage on the emitter will fluctuate, which will cause the collector voltage also fluctuates. The amount of frequency fluctuation is comparable with the frequency of the incoming audio signal.

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Circuits of audio pre-Amp mic

A microphone preamp is a preamplifier used to amplify a microphone's low output voltage to a stronger, more usable level. A microphone preamp must provide stable gain for small signals without being sensitive to induced noise from cabling and without distorting large amplitude signals. Most microphones must be used in conjunction with a microphone preamp to function properly.

Simple audio Pre-Amp mic

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This circuits use infront an RF oscilator to make an RF transmitter that is very sensitive to sound

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