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 LISTResistors:
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.
