22 Watt Car Subwoofer Amplifier Circuit

This is a design amplifier that intended to be connected to an existing car stereo amplifier, adding the often required extra "punch" to the music by driving a subwoofer. As very low frequencies are omni directional, a single amplifier is necessary to drive this dedicated loudspeaker. The power amplifier used is a good and cheap BTL (Bridge Tied Load) 13 pin IC made by Philips (now NXP Semiconductors) requiring a very low parts count and capable of delivering about 22W into a 4 Ohm load at the standard car battery voltage of 14.4V. This is the figure of the circuit;

The stereo signals coming from the line outputs of the car radio amplifier are mixed at the input and, after the level control, the signal enters the buffer IC1A and can be phase reversed by means of SW1. This control can be useful to allow the subwoofer to be in phase with the loudspeakers of the existing car radio. Then, a 12dB/octave variable frequency Low Pass filter built around IC1B, Q1 and related components follows, allowing to adjust precisely the low pass frequency from 70 to 150Hz. Q2, R17 and C9 form a simple dc voltage stabilizer for the input and filter circuitry, useful to avoid positive rail interaction from the power amplifier to low level sections.

Parts:

P1_____________10K Log Potentiometer
P2_____________22K Dual gang Linear Potentiometer
R1,R4___________1K 1/4W Resistors
R2,R3,R5,R6____10K 1/4W Resistors
R7,R8_________100K 1/4W Resistors
R9,R10,R13_____47K 1/4W Resistors
R11,R12________15K 1/4W Resistors
R14,R15,R17____47K 1/4W Resistors
R16_____________6K8 1/4W Resistor
R18_____________1K5 1/4W Resistor
C1,C2,C3,C6_____4µ7 25V Electrolytic Capacitors
C4,C5__________68nF 63V Polyester Capacitors
C7_____________33nF 63V Polyester Capacitor
C8,C9_________220µF 25V Electrolytic Capacitors
C10___________470nF 63V Polyester Capacitor
C11___________100nF 63V Polyester Capacitor
C12__________2200µF 25V Electrolytic Capacitor
D1______________LED any color and type
Q1,Q2_________BC547 45V 100mA NPN Transistors
IC1___________TL072 Dual BIFET Op-Amp
IC2_________TDA1516BQ 24W BTL Car Radio Power Amplifier IC
SW1____________DPDT toggle or slide Switch
SW2____________SPST toggle or slide Switch capable of withstanding a current of at least 3A
J1,J2__________RCA audio input sockets
SPKR___________4 Ohm Woofer or two 8 Ohm Woofers wired in parallel

Wide Band High Frequency Amplifier Circuit

Here’s a circuit for high-frequency amplifier circuit using wide frequency band between 75-150 MHz with transistors, a PNP amplifier. To enhance the signal strength. Before the receiver of the phone. Or FM radio or amateur radio. If high-frequency signals, in particular, its VHF. The booster circuit is one, serves to amplify the signal strength only. This is the figure of the circuit;

Operation of the circuit. High-frequency range VHF, inductive antenna, to the emitter pin of the transistor Q1. so circuit held, in conjunction with the bass, a nice low output impedance. You can use a special access code 50 ohms, the antenna on the circuit at all. Signal at the Q1 will be expanded to increase. And sent to a tuner or receiver to the receiver. The L1 coil wire enamel No. 24 SWG, thousands of rounds of 10, inside diameter 3 mm. And the coil L2 wire number. Thousands of 13 turns, diameter 5 mm. Stent both as a non-core, or an air core. The power supply is +5 V, this circuit while current is 2.5 mA. If the components to use. Should be based on the antenna. And design of high frequency printed circuit boards as well.

TDA1514 Audio Amplifier Circuit

Here’s a circuit for TDA1514 audio amplifier circuit that is capable to provide a high audio power output using a specialized audio IC and other few common components. The TDA1514 audio IC is manufactured by Philips Semiconductor and is capable to provide an output audio power up to 50 W. TDA1514 50W audio amplifier supports 4 or 8 ohms loads and require few external components. This is the figure of the amplifier circuit diagram;

This 50W audio amplifier support a wide input voltage range from 10 volts up to 30 volts and it has many other build in features like: low harmonic distortion, low inter modulation distortion, low offset voltage, good ripple rejection, mute/stand-by facilities, thermal protection, protected against electrostatic discharge, very low thermal resistance, Safe Operating Area (SOAR) protection.

TDA7850 Car Power Amplifier Circuit

Here’s a design circuit for very simple class AB power amplifier designed in MOSFET technology which use just few external components. Tda7850 power amplifier can be used in car radio audio systems. This is the figure of the circuit;

MOSFET output power stage, Hi-Fi class distortion, Low output noise, ST-BY function, Mute function, auto mute at minim supply voltage detection, Output short circuit to ground, to Vs protection, Overrating chip temperature with soft thermal limiter, Output DC offset detection. The TDA7850's inputs are ground-compatible and can stand very high input signals (±8Vpk) without any performance degradation. Standby and Muting facilities are both CMOS compatible. In true CMOS ports or microprocessors are absent the ST-BY pin can be connected direct to Vs but it’s necessary to connect a 470kΩ resistance between these two pins (Vs and ST-BY). The power supply for TDA7850 power amplifier must be 14.4 volts. The TDA7850 IC must be mounted on a corresponding heat sink for high temperature dissipation.

TDA2005 Audio Amplifier Circuit

Here’s a circuit for car radio audio amplifier circuit is specially designed to work on devices like: car radios, cd-players and similar devices. The car radio audio amplifier circuit is based on the TDA2005 audio IC which can provide a maximum output power of 20 watts into a 4 ohms load, connected in bridge mode configuration. This is the figure of the circuit;

The TDA2005 audio amplifier IC can work in even in bridge mode or stereo mode configuration.  The TDA2005 audio IC is a class B audio amplifier designed in a Multiwatt 11 package and can be ordered in two types TDA2005M used for bridge mode application or TDA2005S used in stereo applications. If the TDA2005 is used in stereo mode it can deliver a 10 + 10 watts output power in a 2 ohms load. The advantage of using the TDA2005 audio amplifier in bridge mode configuration is that the total harmonic distortion (THD) is 1% and the THD for  the stereo configuration  mode is 10 %. The Tda2005 audio amplifier IC supports a wide range of input voltage from 8 volts up to 18 volts. The TDA2005 main features are:  short circuit protection, overrating chip temperature, low external components required , bridge or stereo booster amplifiers with or without boostrapand with programmable gain and bandwidth , no electrical isolation between the package and the heat sink .

Photodiode Amplifier Circuit

All photo generators display some voltage dependence of both speed and linearity. It is obvious that the current through a photoconductive cell will not display strict proportionality to incident light if the cell terminal voltage is allowed to vary with cell conductance. Somewhat less obvious is the fact that photodiode leakage and photovoltaic cell internal losses are also functions of terminal voltage. This is a circuit that can be used for amplifier the photo diode;

The current to voltage transducer circuit neatly sidesteps gross linearity problems by fixing a constant terminal voltage, zero in the case of photovoltaic cells and a fixed bias voltage in the case of photoconductors or photodiodes. [Circuit diagram source: National Semiconductor Application]

LM10 Single Cell Microphone Amplifier Circuit

This is a design circuit for a Single-cell microphone amplifier circuit. This circuit produces a voltage gain of 60 dB at 500Ω load with bandwidth 5 kHz. This circuit can provide a 60dB gain up to 10 kHz if it is unloaded. This circuit has a 10 kΩ input impedance. Here’s the figure of the circuit;

This circuit cannot neither produces an output swing closer than 800mV or below 150mV to the supply. However this circuit still has an input noise of 40 to 50 nV/√Hz. [Circuit diagram source: National Semiconductor Application Notes]

Two Stage Phono Pre-Amplifier Circuit with Very Accurate RIAA Response Curve

This is a design circuit that can be used to produce a pre-amplifier with accurate RIAA response, this circuit use two stages of amplifier. This circuit is more complex than single op-amp RIAA pre-amp, but the performance is excellent in terms of accurate frequency response. This is the figure of the circuit;

The circuit uses LM833 high performance op-amp from National Semiconductor, giving the best performance of 0.1 dB response curve error, compared to the standard RIAA curve. [Circuit diagram source: National Semiconductor Application Notes]

Signal Conditioning Amplifier Circuit for Piezofilm Sensor

This circuit is design for the signal can be converted by piezoelectric films in many ways such as thermal to electrical (temperature sensor), mechanical to electrical (microphone), and electrical to mechanical (a loudspeaker). The circuit is signal conditioning amplifier for piezofilm sensor which uses three op amps and has a high-input-impedance differential charge. This is the figure of the circuit;

This circuit uses a voltage source with a capacitor in series as the electrical analog of a piezofilm sensor. The differential charge amplifier is endowed by a dual op amp (IC1) with low supply current and single-supply operation. The input common-mode voltage  is set by a small bypass capacitor (C3), R2, R1 at the mid-supply level. The C1 and C2 are used to set AC gain for the differential stage. A gain of C1/CEQ is 96.

The differential amplifier also is used to act as a first-order high-pass filter. The resistors R9, R8, R6, and R5 with IC2 perform differential-to-single-ended conversion. Using the values shown, the different gain is 20. [Circuit diagram source: maxim-ic.com]

Op Amp Voltage Regulator Circuit

This is a simple voltage regulator circuit that employs an operational amplifier (op-amp).  As its name implies, this circuit accepts an unregulated voltage input (i.e., a fluctuating input voltage), and provides a regulated voltage output (a stable output voltage that remains at or very close to its intended output level).  The unregulated input voltage must be higher than the desired output level by a sufficient margin in order to achieve 'effective' regulation. This is the figure f the circuit;

The zener diode Vz acts as a voltage reference for the circuit, and is fed into the non-inverting input of the operational amplifier.  The voltage divider formed by R1 and RF sets the voltage level of the inverting input of the op amp, which is basically a feedback from the circuit output to the op amp.  The NPN transistor is used to boost the output current of the circuit. The voltage at the non-inverting input of the op amp is pegged at the zener voltage, while the voltage at the inverting input is always a fraction of the output voltage as defined by RF and R1.  When the output exceeds the set level, the inverting input voltage exceeds that of the non-inverting input, causing the output of the op-amp to go 'low'.  This turns off the NPN transistor, causing the output voltage to dip.  When the output goes below the set level, the reverse happens, i.e., the op-amp's output goes 'high', causing the NPN transistor to turn on and pull the voltage up.

         

Thus, this circuit works by turning off the transistor when the output voltage is too high and turning it on when the output is too low.  This balancing act happens continuously, with the circuit reacting instantaneously to deviations in the output voltage.  Resistor RF is adjusted to set the desired output voltage of the circuit.  The zener diode needs to be replaced by a voltage reference IC if a more stable and more precise output is required.

BTL Mono Amplifier with DC Volume Control Circuit

This is the circuit for BTL  (bridged tied load) mono amplifier with DC volume Control circuit. This circuit uses TDA7052A/AT that is suitable not only for monitors and TV but also battery fed portable radios and recorders. The difference between conventional DC volume circuits and TDA7052A/AT the DC volume control is there is no coupling capacitor is needed in TDA7052A/AT the DC volume control to maintain the low offset voltage. This is the figure of the circuit;

Besides that, the TDA7052A/AT the DC volume control requires low supply. The advantages of BTL principle are it has the ripple’s frequency on the supply voltage is twice the signal frequency and the supply current peak is lower. To save the cost, a smaller capacitor can be used. The BTL principle can be implemented in portable application that will decrease supply voltage but increases the output power. This amplifier has maximum gain of 35.5 dB. The mute mode is when the DC volume control voltage is below 0.3V. This circuit also equipped with thermal protection. The gain will be decreased when temperature reach +150 C. [Circuit's schematic diagram source: nxp.com]

Low Impedance Microphone Input Preamplifier Circuit

This is a circuit for a low-impedance (Z = 50 to 200 ohms) microphone input circuit or pre-amplifier that employs low-cost, low-noise precision operational amplifiers such as the OP27 and the OP37. This is the figure of the circuit;

The simple circuit above amplifies differential signals from low-impedance microphones by 50 dB.  Because of the high working gain of the circuit, use of the OP37 (which is a high-speed op amp) is recommended if bandwidth is important to the application.  To ensure stability, a dummy resistor Rp must be placed between the OP37 inputs. This will prevent amplifier oscillation due to 100% feedback from the open input in case the microphone is unplugged.     
 

IL300XC Isolation Amplifier Circuit for TMP01 Temperature Sensor

This is a design circuit for about IL300XC Isolation Amplifier circuit for TMP01 Temperature Sensor. This circuit is used in an environment that needs to be electrically isolated from the central processing area. This circuit uses an 8-pin opto isolator (IL300XC). IL300XC was chosen because it can operate across a 5,000V. To drive the LED connected between Pin 2 and Pin 1, this circuit uses an OP290 single-supply amplifier. The photodiode connected from Pin 3 to Pin 4 gives the feedback. This is the figure of the circuit;

The OP290 drives the LED, that there is enough current generated in the photodiode to exactly equal the current derived from the VPTAT voltage across the 470 kO resistor. On the receiving end, the current from the second photodiode is converted to a voltage through its feedback resistor R2. TO buffer the 2.5 V reference voltage of the TMP01, this circuit uses the other amplifier in the dual OP290. It will give the an accurate, low drift LED bias level without affecting the programmed hysteresis current. The bias level accuracy at receiving end is provided by A REF43.

The current of the photodiode is determined by following equation:
I1=(2.5V-VPTAT)/470K
The output voltage is determined by following equation:
Vout=2.5V-I2*R2
=2.5V-0.7*((2,5V-VPTAT)/470)*644K=VPTATT

R2 must be larger than R1 to achieve overall unity gain because the gain of IL300XC is less than 1.0. To correct for the initial gain accuracy of the IL300XC, A trim is used in this circuit. Just adjust the trim to get output voltage equal to VPTAT at any particular temperature. Both the OP90 and REF43 contribute no significant error because of drift and operate from a single supply.

Low Impedance Microphone Amplifier Circuit

This is a circuit for microphone amplifier for low impedance. This circuit is based on transistor for controller the circuit. This is the figure of the circuit;

This circuit is use with low impedance (~200 ohm) microphones. It will work with stabilized voltages between 6-30VDC. If you don't build the impedance adapter part with T1, you get a mic amp for higher impedance microphones. In this case, you should directly connect the signal to C7.

Part:
R1=15k
R2= 150k
R3= 2k2
R4= 820
R6= 10k
R7= 10k
P1= 1M
C1= 3k9
C2= 100u
C3= 22u
C4= 4u7
C5= 470u
C6= 10u
C7= 100n
C8= 47u UNIPOLAR
D1= 1N4148
U1= TL081
CN1= SIL6

10W Power Amplifier Using TDA2003 IC’s

This is a design circuit for power amplifier that is the circuit diagram of a 10W audio amplifier using the popular TDA2003 IC from SGS Thomson. This is the figure of the circuit;


The IC can easily deliver 10W to a 4 Ohms load at 18V DC supply voltage. The IC can be also operated from 12V and that makes it applicable in car audio systems. The useful features of TDA2003 includes short circuit protection between all pins, thermal overload protection, low harmonic distortion, low cross over distortion etc.

Small Amplifier Circuit Using Transistors

This is a design circuit for audio amplifier circuit. When audio is detected, the output is push-pull and consumes less than 3mA (with no signal) but drives the earpiece to a very loud level. It’s extremely difficult to set up because the whole circuit is DC coupled. Basically you don’t know where to start with the biasing. 8k2 between the emitter of the first transistor and 0v rail and the 470R resistor are the two most critical components. This is the figure of the circuit;


The emitter voltage on the BC 547 is set by the 8k2 across the 47u and this turns it on. To call the driver transistor, the collector is directly connected to the base of a BC 557. Current flow through the 1k and 470R resistors so that the voltage developed across each resistor turns on the two output transistors is caused by these transistors and the output of BC 557 are now turned on. The end result is mid-rail voltage on the join of the two emitters. Major negative feedback is provided by 8k2 feedback resistors while the 330p prevents high-frequency oscillations occurring.

[Circuit diagram source: Talking Electronics]

Audio Amplifier Circuit with DC Volume Control

This is a design circuit for audio power amplifier. This circuit uses based on TDA7052B. The TDA7052B and TDA7052BT are 0.5 W and 1 W mono Bridge-Tied Load (BTL) output amplifiers with DC volume control. Not only have been designed for use in TV and monitors, but TDA7052B and TDA7052BT are also suitable for use in battery-fed portable recorders and radios. This is the figure of the circuit;


This devices are integrated with a Missing Current Limiter (MCL). When the difference in current between the output terminal of each amplifier exceeds 100 mA (300 mA typ), the MCL circuit is activated. Headphone application will be allowed on this 100mA level (single-ended).
[Circuit source: NXP Application Note]

Audio Amplifier Circuit with DC Volume Control

This is a design circuit for audio power amplifier. This circuit uses based on TDA7052B. The TDA7052B and TDA7052BT are 0.5 W and 1 W mono Bridge-Tied Load (BTL) output amplifiers with DC volume control. Not only have been designed for use in TV and monitors, but TDA7052B and TDA7052BT are also suitable for use in battery-fed portable recorders and radios. This is the figure of the circuit;

This devices are integrated with a Missing Current Limiter (MCL). When the difference in current between the output terminal of each amplifier exceeds 100 mA (300 mA typ), the MCL circuit is activated. Headphone application will be allowed on this 100mA level (single-ended).

[Circuit source: NXP Application Note]

Boosted Class D Audio Power Amplifier Circuit

This is a circuit of the power amplifier that is regulate by LM48510. This is a simple basic form circuit. This is the figure of the circuit;

The IC integrates a boost converter with a high efficiency mono, Class D audio power amplifier to provide 1.2W continuous power into an 8Ω speaker when operating on a 3.3V power supply with boost voltage (PV1) of 5.0V. When operating on a 3.3V power supply, the LM48510 is capable of driving a 4Ω speaker load at a continuous average output of 1.7W with less than 1% THD+N. The LM48510 is designed for use in mobile phones and other portable communication devices. The high (76%) efficiency extends battery life when compared to Boosted Class AB amplifiers. The LM48510 features a low-power consumption shutdown mode. Shutdown may be enabled by driving the Shutdown pin to a logic low (GND). The gain of the Class D is externally configurable which allows independent gain control from multiple sources by summing the signals. Output short circuit and Thermal shutdown protection prevent the device from damage during fault conditions. Superior click and pop suppression eliminates audible transients during power-up and shutdown.

2.5W Audio Power Amplifier Circuit

This is a circuit design for power amplifier that it has a low gain amp for the output signal. This circuit is based on LM380 op amp IC. This is the figure of the circuit;

The output is short circuit proof with internal thermal limiting. The package outline is standard dual-in-line. The LM380N uses a copper lead frame. The center three pins on either side comprise a heat sink. This makes the device easy to use in standard PC layouts. Uses include simple phonograph amplifiers, intercoms, line drivers, teaching machine outputs, alarms, ultrasonic drivers, TV sound systems, AM-FM radio, small servo drivers, power converters, etc.