Showing posts with label circuits. Show all posts
Showing posts with label circuits. Show all posts

Thursday, November 20, 2014

65W Power Amplifier Circuits with HEXFET

65W65W Power Amplifier Circuits with HEXFET

A average ability amplifier that is characterized by a lot of acceptable complete quality, but accompanying is actual simple in the construction. Him uses, abundant time in my alive loudspeakers. In his achievement date abide the actual acceptable FET transistors, technology HEXFET, transistor which are controlled by voltage and no by accepted as the classically bipolar transistors. The ambit has balanced designing, absolute appropriately the harmonic baloney problem.

All the transistors that are acclimated in the ambit are simple and they abide in big clearings in the market. The pairs of cogwheel amplifiers Q1-2 and Q3-4 should be akin amid them and abreast the one in the other. Appropriately you can buy abundant transistors of types BC550C and BC560C, and with a multimeter you bout amid them creating pairs with aforementioned characteristics, ensuring appropriately compatible behavior in the temperature changes etc. Networks RC from the R7/C3 and R12/C4 abatement the bandwidth of cogwheel amplifiers and ability amplifier in the 6.5MHZ. Resistors R8-9-10-11 action as bounded acknowledgment in the cogwheel amplifiers convalescent the linearity. The cogwheel amplifiers are supplied with connected accepted from him accepted sources Q5 and Q6. The bent of accepted sources becomes from the aggregate of diodes LED D1, D2 and R20.

This becomes because the aggregate transistor/LED ensures big thermic stability, for this acumen should they are in actual abreast ambit [1]. With the TR1 trimmer we adapt the bent accepted of achievement ability stage. For this acumen Q8 should acquisition itself on the heatsink so that it ensures thermic adherence in the bias, so that it does not change with the temperature changes. The resistors R32-33 appearance a bounded acknowledgment bronchus in the achievement stage, because this functions as voltage amplifier.

With the TR1, R3-4, C14 we adapt the amplifier achievement DC account voltage, abreast in the zero. The transistors Q8-10-11-12-13, [Fig.1] should are placed on heatsink, abacus amid the transistors and the heatsink of acceptable affection leaves mica and ointment. Inductor L1 is constituted by 6 coils of cloistral cupreous wire of bore 1.5mm, with centralized inductor bore of 16mm

Monday, November 17, 2014

MP3 Car Amplifier Schematic Circuits 150W

MP3MP3 Car Amplifier Schematic Circuits 150W

These accessories are low cost, aerial speed, bifold JFET ascribe operational amplifiers with an internally akin ascribe account voltage (BI-FET II technology). They crave low accumulation accepted yet advance a ample accretion bandage amplitude artefact and fast bulk rate. In addition, able-bodied akin aerial voltage JFET ascribe accessories accommodate actual low ascribe bent and account currents. The LF353 is pin accordant with the accepted LM1558 acceptance designers to anon advancement e the all-embracing achievement of absolute LM1558 and LM358 designs. These amplifiers may be acclimated in applications such as aerial acceleration integrators, fast D/A converters, sample and authority circuits and abounding added circuits acute low ascribe account voltage, low ascribe bent current, aerial ascribe impedance, aerial bulk amount and advanced bandwidth. The accessories additionally display low babble and account voltage drift. (National Semiconductor

Internally trimmed offset voltage: 10 mV
Low input bias current: 50pA
Low input noise voltage: 25 nV
Low input noise current: 0.01 pA
Wide gain bandwidth: 4 MHz
High slew rate: 13 V/us
Low supply current: 3.6 m
High input impedance: 1012.
Low total harmonic distortion : <>

Wednesday, October 29, 2014

MP3 Player Booster Circuits

MP3 players are all the rage these days. The smaller ones in memory-stick format are particularly easy to take with you; your very own ‘personal sound system’ on the move! It’s when you want others to share your taste in music that you find these players to have a lack of power. You can get round this problem with the help of the MP3 booster, a small amplifier that can be used to connect your MP3 player directly to your Hi-Fi. When you next invite your friends to a party you can ask them to bring their ‘personal music’ as well as the usual drinks!

But first we have to build this booster! The small battery-powered players have an output signal that is more than sufficient to drive a set of 32 Ohm headphones. You’ll often find that with an output of 1mW the sound pressure level (SPL) produced can reach up to 90 dB. This would be sufficient to cause permanent damage to your hearing after only one hour! The maximum output voltage will then be around 200mV. This, however, is insufficient to fully drive a power amplifier. For this you’ll need an extra circuit that boosts the output voltage.

Power amps usually require 1 V for maximum output, hence the signal has to be amplified by a factor of five. We will also have to bear in mind that quieter recordings may need to be amplified even more. We’ve used a simple method here to select the gain, which avoids the use of potentiometers. After all, the MP3 player already has its own volume control. We decided to have two gain settings on the booster, one of three times and the other ten times. Amplifiers IC1A and IC1B (for the right and left channels) are housed in a single package, a TS922IN.

The output signal of the MP3 player is fed via a stereo cable and socket K1 to the inputs of the amplifiers. The gain depends on the relationship between resistors R2 and R1 (R6 and R5 for the other channel) and is equal to ten times. When you add jumper JP1 (JP2), resistor R3 (R7) will be connected in parallel with the negative feedback resistor R1 (R6), which causes the gain to be reduced to about three. When you start using the booster you can decide which gain setting works best for you.

Circuit diagram:


MP3 Booster Circuit Diagram

Resistor R4 (R8) takes the amplified MP3 signal to the output socket K2 (K3). A cable then connects these phono sockets to the input of your power amplifier. The resistors connected in series with the output (R4 and R8) are there to keep the booster stable when a long cable is connected to its output. Cables have an unwelcome, parasitic capacitance. This capacitive effect could (due to phase shifts of the signal) affect the negative feedback of the booster in such a way that a positive feed back occurs, with the result that the booster oscillates and possibly damages the power amplifier!

The resistors (R4 and R8) effectively isolate the output of the booster from the parasitic capacitance of the output cable. They also protect the booster outputs from short circuits. We’ve used a TS922IN opamp in this booster because it can operate at very low supply voltages (the maximum is only 12 V!), but can still output a reasonable current (80 mA max.). For the supply we’ve used rechargeable batteries (e.g. NiCd or NiMH cells) so that we don’t need a mains supply.

To keep the number of cells required as small as possible, we’ve chosen a supply voltage of 5 volt; this can be supplied by four rechargeable batteries. It is also possible to use four ordinary, non-rechargeable batteries; it’s true that the supply voltage then becomes a bit higher (6 Volts), but that won’t cause any harm. Since we’ve used a symmetrical supply for the booster (2 x 2 batteries), it will be easiest if you use two separate battery holders, each with two AA cells. The two holders are connected in series.

Make sure that the batteries are connected the right way round; the positive of one always has to be connected to the negative of the next. This also applies to the connection between the two battery holders. S1A/B is a double pole switch, which is used to turn both halves of the battery supply on or off simultaneously. If you can’t find the (dual) opamp we’ve used (or an equivalent), you could always use standard opamps such as the NE5532, TL082 or TL072. These do need a higher supply voltage to operate properly. In these cases you should use two 9 V batteries and replace resistor R9 with a 15 kΩ one.

Do take care when you connect the circuit to your power amplifier because the output signal can be a lot larger and you could overload the power amplifier. (Although you’re more likely to damage the loudspeakers, rather than the amplifier!) (Please note that these two 9 V batteries can’t be used as a supply for the TS922IN!) In our circuit we’ve used a stereo jack socket for the input and phono sockets for the output because these are the most compatible with MP3 players and power amplifiers respectively. If you wanted to, you could solder shielded cables directly to the circuit instead, with the correct plugs on the ends. You’ll never find yourself without the correct connection leads in that case!
Source: Elektor Electronics 12-2006

Wednesday, September 24, 2014

Phonon Preamplifier Circuits Diagram

In recent years, following CDs introduction, vinyl recordings are almost disappeared. Nevertheless, a phonon preamplifier is still useful for listening old vinyl discs from a well preserved collection. This simple but efficient circuit devised for cheap moving-magnet cartridges, can be used in connection with the audio power amplifiers shown in these webpages, featuring low noise, good RIAA frequency response curve, low distortion and good high frequency transients behavior due to passive equalization in the 1 to 20KHz range. Transistors and associated components provide ±18V supply to the op-amp, improving headroom and maximum output voltage.

Phono Preamplifier Circuits Diagram
Phono Preamplifier Circuits Diagram
 Notes:
  • R2, R3, R4, R7, R8, C4 & C5 should be low tolerance types.
  • Schematic shows left channel and power supply.
  • For stereo operation R1, R2, R3, R4, R7, R8; J1; C1, C4 & C5 must be doubled.
  • Numbers in parentheses show IC1 right channel pin connections.

Technical data:

Sensitivity @ 1KHz: 2.5mV RMS input for 200mV RMS output
Max. input voltage @ 1KHz:120mV RMS
Max. input voltage @ 10KHz:141mV RMS
Max. input voltage @ 20KHz:127mV RMS
Frequency response @ 1V RMS output: 100Hz to 20KHz ±0.5dB; -0.75dB @ 30Hz
Total harmonic distortion @ 1KHz and 6V RMS output: 0.006%
Total harmonic distortion @10KHz and 1V RMS output: 0.02%

Parts:

R1_________47K   1/4W Resistor
R2________100R   1/4W Resistor
R3__________6K8  1/4W Resistor
R4_________68K   1/4W Resistor
R5,R6_______2K7  1/4W Resistor
R7__________2K2  1/4W Resistor
R8_________39K   1/4W Resistor
 
C1-C3_____100µF  25V Electrolytic Capacitors
C4,C5______47nF  63V Polyester Capacitors 5% tolerance
 
D1,D2__BZX79C18  18V 500mW Zener Diodes
 
IC1_______LM833  Low noise Dual Op-amp
 
Q1________BC337  45V 800mA NPN Transistor
Q2________BC327  45V 800mA PNP Transistor
 
J1__________RCA  audio input socket


Precision Audio Milli volt meter Circuits Diagram

This electronic circuit is audio milivolt meter. It measures 10mV to 50Volt RMS in eight ranges.

Precision Audio Millivoltmeter Circuits Diagram

Precision Audio Millivoltmeter Circuits Diagram
 
 Notes:
  • Connect J2 and J3 to an Avo-meter set to 50µA range:
  • Switching SW2 the four input ranges will be multiplied by 5
  • Total fsd ranges are: 10mV, 50mV, 100mV, 500mV, 1V, 5V, 10V, 50V
  • Set R11 to read 1V in the 1V range, with a sine wave input of 1V @ 1KHz
  • Compare the reading with that of another known precision Millivoltmeter or with an oscilloscope.
  • The oscilloscope reading must be a sinewave of 2.828V peak to peak amplitude
  • Frequency response is flat in the 20Hz-20KHz range
  • If you have difficulties in finding resistor values for R1, R2, R3 & R4, you can use the following trick:
    R1 = 10M + 1M in parallel
    R2 = 1M + 100K in parallel
    R3 = 100K + 10K in parallel
    R4 = 1K2 + 6K8 in parallel
    All resistors 1/4W 1% tolerance 

Parts:

R1_____909K    1/2W 1% Metal Oxide Resistor
R2______90K9   1/2W 1% Metal Oxide Resistor
R3_______9K09  1/2W 1% Metal Oxide Resistor
R4_______1K01  1/2W 1% Metal Oxide Resistor
R5_____100K    1/4W Resistor
R6_______2M2   1/4W Resistor
R7______82K    1/4W Resistor
R8______12K    1/4W Resistor
R9_______1K2   1/4W Resistor
R10______3K3   1/4W Resistor
R11____200R    1/2W Trimmer Cermet
 
C1_____330nF   63V Polyester Capacitor
C2,C3__100µF   25V Electrolytic Capacitor
C4_____220µF   25V Electrolytic Capacitor
C5______33pF   63V Polystyrene Capacitor
C6_______2µ2   63V Electrolytic Capacitor
 
D1-D4___1N4148 75V 150mA Diodes
 
IC1_____CA3140 Op-amp
IC2_____CA3130 Op-amp
 
SW1_____2 poles 5 ways rotary switch
SW2_____SPDT switch
 
J1______RCA audio input socket
J2,J3___4mm. output sockets
 
B1______9V PP3 Battery
 
Clip for PP3 Battery