Wednesday, November 24, 2010
200 WATT AUDIO AMPLIFIER
Load Resistance : 8ohms
Input impedance : 55K
Maximum supply voltage : (+95v)-0-(-95v)
Recommended supply voltage : (+66v)-0-(-66v)
Thursday, September 9, 2010
FM Transmitter 4Watt
Stabilised tendency of catering: Vcc=12~16V
Frequency of emission: 88~108MHz
Consumption: 100~400mA
The resistors are 1/4W.
R1, R2 10KOhm
R3 47Ohm
C1, C2 1nF
C3 4,7uF/16V
C4, C7, C8 0~45pF trimmer
C5, C6 10pF
C9 100nF
L1 4 turns, 7mm diameter *
L3 3 turns, 7mm diameter *
L4 5 turns, 7mm diameter *
L2 RFC (resistance 1MOhm with wrapped around her inductor of enough coils from fine isolated wire. Scratch of utmost inductor and you stick in utmost the resistance making thus a parallel L-r circuit.)
T1, T2 2N2219
ANT Simple dipole l/2.
MIC IN Microphone dynamic or other type. (It can also connected to a cassette player unit)
* The inductors is air from wire of coaxial 75W or other 1mm roughly.
Before you print it out with microsoft paints, set the screen resolution to 1280 by
With the C4 we regulate the frequency.
With their C7, C8 we adapt the resistance of aerial (practically to them we regulate so that it is heard our voice in the radio as long as you become cleaner).
The T2 wants refrigerator.
Friday, August 13, 2010
Radio only 1 transistor without electricity
In many designs we've seen radios that operate without power, but all are known to use the diode 1N34. (Crystal Radio).
Although significant improvements have increased the sensitivity and selectivity of these system circuits, Performances were limited until new techniques have emerged.
Here we have the first transistor radio that works without batteries, it is powered by random electric fields are everywhere in the atmosphere.
This circuit is a medium wave receiver and attaches easily to frequencies from 500Khz to 11Mhz.
To get good results in the reception of radio stations, we should give great importance to the ground and the antenna.
To listen to distant and weak stations we have to use a battery 9volt parallel with the capacitor C4 with it's positive side between R2 and C4.
The coils are in the frequency of 500-1500Khz is tight and closely wrapped.
The coils are in frequency of 1.5-11Mhz is more tighter and more closely wrapped.
Thursday, July 29, 2010
100W Audio Amplifier
- Clean the component leads with a small piece of emery paper. - Bend them at the correct distance from the component body and insert the component in its place on the board.
- You may find sometimes a component with heavier gauge leads than usual, that are too thick to enter in the holes of the p.c. board. In this case use a mini drill to enlarge the holes slightly. Do not make the holes too large as this is going to make soldering difficult afterwards.
- Take the hot iron and place its tip on the component lead while holding the end of the solder wire at the point where the lead emerges from the board. The iron tip must touch the lead slightly above the p.c. board.
- When the solder starts to melt and flow, wait till it covers evenly the area around the hole and the flux boils and gets out from underneath the solder. The whole operation should not take more than 5 seconds. Remove the iron and leave the solder to cool naturally without blowing on it or moving the component. If everything was done properly the surface of the joint must have a bright metallic finish and its edges should be smoothly ended on the component lead and the board track. If the solder looks dull, cracked, or has the shape of a blob then you have made a dry joint and you should remove the solder (with a pump, or a solder wick) and redo it.
- Take care not to overheat the tracks as it is very easy to lift them from the board and break them.
- When you are soldering a sensitive component it is good practice to hold the lead from the component side of the board with a pair of long-nose pliers to divert any heat that could possibly damage the component.
- Make sure that you do not use more solder than it is necessary as you are running the risk of short-circuiting adjacent tracks on the board, especially if they are very close together.
- When you finish your work cut off the excess of the component leads and clean the board thoroughly with a suitable solvent to remove all flux residues that still remain on it.
- See that there are no components missing or inserted in the wrong places.
- Make sure that all the polarised components have been soldered the right way round. - Make sure the supply has the correct voltage and is connected the right way round to your circuit.
- Check your project for faulty or damaged components. If everything checks and your project still fails to work, please contact your retailer and the Smart Kit Service will repair it for you.
Wednesday, July 7, 2010
1V, Low-Power, Stereo Headphone Amplifier with Shutdown (MAX9725)
The MAX9725A–MAX9725D fixed-gain, stereo headphone amplifiers are ideal for portable equipment where board space is at a premium. The MAX9725E offers the flexibility to adjust the gain with external input and feedback resistors. The MAX9725A–MAX9725E use a unique DirectDrive® architecture to produce a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors, saving cost, board space, and component height. Fixed gains of -2V/V (MAX9725A), -1.5V/V (MAX9725B), -1V/V (MAX9725C), and -4V/V (MAX9725D) further reduce external component count. The adjustable gain of the MAX9725E DirectDrive headphone amplifier allows for any gain down to -1V/V using external resistors.
The MAX9725 delivers up to 20mW per channel into a 32Ω load and achieves 0.006% THD+N. An 80dB at 1kHz power-supply rejection ratio (PSRR) allows the MAX9725 to operate from noisy digital supplies without an additional linear regulator. The MAX9725 includes ±8kV ESD protection on the headphone output. Comprehensive click-and-pop circuitry suppresses audible clicks and pops at startup and shutdown. A low-power shutdown mode reduces supply current to 0.6µA (typ).
The MAX9725 operates from a single 0.9V to 1.8V supply, allowing the device to be powered directly from a single AA or AAA battery. The MAX9725 consumes only 2.1mA of supply current, provides short-circuit protection, and is specified over the extended
Sunday, June 27, 2010
Amplifier 250-500W with transistors MJ15003.
General Specifications
Rated Power Output
(20Hz to 20kHz Continuous Average Sine Wave)
250 watts into 8 ohms
500 watts into 4 ohms
Power Bandwidth
(250 watts into 8 ohms)
20Hz to 40kHz (0dB to -3dB)
Frequency Response
1 watt into 8 ohms
20Hz to 100kHz (0dB to -1.0 dB)
250 watts into 8 ohms
20Hz to 20kHz (Flat)
Input Sensitivity
+3 dBV
(1.4V RMS produces an output of 350 watts into 8 ohms)
Input Impedance
33K ohms, Unbalanced
Rise Time
2.0 microSeconds
Total Harmonic Distortion (THD)
Full Power(250 watts into 8 ohms)
Less than 0.007 % THD @ 1kHz
Less than 0.08 % THD @ 20Hz to 20kHz
Half Power (125 watts into 8 ohms)
Less than 0.003 % THD @ 1kHz
Less than 0.03 % THD @ 20Hz to 20kHz
10 watts into 8 ohms
Less than 0.003 % THD @ 1kHz
Less than 0.01 % THD @ 20Hz to 20kHz
Wednesday, June 23, 2010
FM Stereo Transmitter ( BH1415F )
Sunday, June 13, 2010
240VAC TO 5VDC POWER SUPPLY
This is simple way to power some 5v logic from a 240vac source. If a 120vac power adapter is used, the circuit will also work for 120vac power lines.
Monday, May 31, 2010
20 LED AUDIO VU METER
Friday, May 7, 2010
TDA1562Q . . . 50W from a 12 V battery (Elektor 2/2000)
technical data
Properties
High power output through Class-H operation
Low power dissipation during reproduction of music signals
Proof against short-circuits
Protection against excessive temperatures
Standby switch
No power-on or power-off clicks
Visible error indication
Measurement results (at Ub=14.4 V)
Supply voltage 8–18 V
Sensitivity 760 mV r.m.s.
Input impedance 70 kΩ
Power output 54 W r.m.s. into 4 Ω (f=1 kHz; THD+N=1%)
Harmonic distortion (THD+N) at 1 W into 4 Ω: 0.046% (1 kHz)
0.29% (20 kHz)
at 35 W into 4 Ω: 0.12% (1 kHz)
0.7% (20 kHz)
Signal-to-noise ratio (with 1 W into 4 Ω) 88 dBA
Power bandwidth 7.5 Hz – 185 kHz (at 25 W into 4 Ω)
Quiescent current about 135 mA (‘on’)
COMPONENTS LIST
Resistors:
R1 = 1MΩ
R2 = 4kΩ7
R3 = 1kΩ
R4 = 100kΩ
Capacitors:
C1,C2 = 470nF
C3,C4 = 10μF 63V radial
C5,C6,C8 = 4700μF 25V radial
(18mm max. dia., raster 7.5 mm)
C7 = 100nF, raster 5 mm
Semiconductors:
D1 = high-efficiency-LED
IC1 = TDA1562Q (Philips)
Miscellaneous:
S1 = single-pole on/off switch
Four spade connectors, PCB mount
Heatsink for IC1 (Rth<2.5>
Monday, April 19, 2010
LM3876 - High-Performance 56W Audio Power Amplifier with Mute
The LM3876 is a high-performance audio power amplifier capable of delivering 56W of continuous average power to an 8
• 56W continuous average output power into 8Ω
• 100W instantaneous peak output power capability
• Signal-to-Noise Ratio >= 95 dB(min)
• An input mute function
• Output protection from a short to ground or to the supplies via internal current limiting circuitry
• Output over-voltage protection against transients from inductive loads
• Supply under-voltage protection, not allowing internal biasing to occur when VEE + VCC <= 12V, thus eliminating turn-on and turn-off transients
• 11-lead TO-220 package
• Wide supply range 20V - 94V
Part list
Resistor:
R1, R3 = 1 k
R2, R4, R5 = 18k
R6 = see text
R7 = 10R, 5 Watt
R8, R9 = 22k
Capacitors:
C1 = 2.2 uF
C2 = 220 uF, 160 V
C3 = 22 uF, 40 V
C4 = 47 pF
C5 = 100 uF, 40 V
C6 = see text
C7, C8 = 100 nF
C9, C10 = 1000 uF, 40 V
Inductors:
L1 = 0.7 uH – see text
Integrated circuits:
IC1 = LM3876T
Miscellaneous:
Heat sink for IC1
Air-cored inductor L1 consists of 13 turns of 1mm dia. enamelled copper wire with an inner diameter of 10mm. The completed inductor is pushed over R7 and its terminals soldered to those of the resistor. All electrolytic capacitors must be mounted upright. The amplifier can be muted with a single-pole switch connected to the MUTE input (pin8). This function is enabled when the switch is open. If muting is not required, solder a wire bridge across the mute terminals on the board. The R6-C6 is not normally required in this application, but provision has been made for it for use in other applications. According to the manufacturers, both chips are optimalized for a load of 8 Ohm. The output power is lower when a 4 Ohm load is used or when the supply voltage is reduced. When a 4 Ohm load is used, the SPIKE protection becomes active when the supply voltage is about 27V, resulting a in a reduction of the power output to 10W. This means that it is not advisable to use loudspeaker with an impedance
Sunday, April 18, 2010
LM1875 - POWER AMPLIFIER 20 WATT
The LM1875 delivers 20 watts into a 4Ω or 8Ω load on ±25V supplies. Using an 8 load and ±30V supplies, over 30 watts of power may be delivered. The amplifier is designed to operate with a minimum of external components. Device overload protection consists of both internal current limit and thermal shutdown.
The LM1875 design takes advantage of advanced circuit techniques and processing to achieve extremely low distortion levels even at high output power levels. Other outstanding features include high gain, fast slew rate and a wide power bandwidth, large output voltage swing, high current capability, and a very wide supply range. The amplifier is internally compensated and stable for gains of 10 or greater.
Features
• Up to 30 watts output power
• AVO typically 90 dB
• Low distortion: 0.015%, 1 kHz, 20 W
• Wide power bandwidth: 70 kHz
• Protection for AC and DC short circuits to ground
• Thermal protection with parole circuit
• High current capability: 4A
• Wide supply range 16V-60V
• Internal output protection diodes
• 94 dB ripple rejection
• Plastic power package TO-220
Wednesday, March 17, 2010
2.5 GHz Frequency Counter with Blue 2x16 LCD display
This project explain a very powerful frequency counter which has many useful software functions.
The software can add or subtract 3 different IF frequencies (±455 kHz ,±10.7 MHz and ±21.4 MHz).
You have also two level of resolutions, 1kHz and 100Hz.
The main oscillator can be on-board 13MHz or external 10 MHz.
The counter data can easy be transmitted to computer with RS232 cable (software below)
The construction is extremely simple and the unit is very small.
This project comes in a KIT version, se more details below.
Background
Once again, It is time to update the frequency counter.
A frequency counter is one of the most important measuring tool we need as homebrew's of RF electronic.
This frequency counter has very high performance and still is very easy to build and to use.
Anyone can build it and have a professional frequency measuring tool.
The counter is based around a LCD display with 2 lines and 16 chars.
I have used a HD44780 based display which is very common.
A PIC16F870 circuit controls all counting and display functions.
A prescaler is added to make it possible to measure up to 2.5GHz with high sensitivity.
The Display Module Size (W x H x T): 80mm X 36mm.
The controller PCB has the same size. This makes the unit very small and slim.
In the menu system of this frequency counter, you can choose between two reference frequencies.
· On-board 13.000MHz crystal (picture at right), or
· External 10.000MHz signal.
The reason of using a external 10.000 MHz reference frequency is because it is common among reference oscillators, as HP Z3801 GPS locked frequency source.
Wednesday, January 27, 2010
6H9C-6П13С PUSH-PULL TUBE AMPLIFIER
The output stage: push-pull, class A, with a fixed offset in 6P13S tubes in triode switch.
Output Power - 10.5 W
Band Frequency - 25Hz ... 30kHz
Sensitivity - 0.707V (1V amplitude)
THD - 1.5% (before clipping), 0.8 ... 0.9% (half power)
The level of background noise on the output - 1.5 mV
Monday, January 11, 2010
TUBE DISTORTION
IC1---LM747 dual op-amp, others may be substitued but pinout will differ
IC2---LM340K 12 Voltage Regulator
Bridge Rectifier - Full wave bridge rectifier, 50Volts, 500ma minimum
All resistors 1/2Watt, 10% prefered