Tuesday, November 30, 2010
Analog Versatile Circuit MIC 640 Acquisition System
The MIC 640 can operate in automatic mode, thus sending the result of four steps every second, or in command mode, in which case it sends the result of four measures under the control of external logic signal. In this latter method that we use here.
Its consumption is extremely low, it is possible to feed signals from the unused serial port RS 232, subject of course not to waste the little energy available in external circuits involved too greedy.
This circuit, easily available in France, costs less than 18 euro which makes it an ideal candidate for this achievement we will find the schema without tarder.Si you want more information about the MIC 640;'s complete data sheet entirely in French, is available for download by clicking this link.
Schematic acquisition module
Analog Versatile Circuit MIC 640 Acquisition SystemHis entry called CTRL to define its mode of operation. Left to the body, it makes it automatically perform a conversion on each input per second, whereas if it is reduced to levels as high as in this case, it triggers a conversion of each entry at each grounding.
These earthed take place through the transistor Q1 controlled by the serial data output TXD of RS 232, via the diode D4. This same output is through the diode D3 and this time the capacitor C3, to produce the negative supply voltage of the input stage that we discover in a moment.
The control lines DTR and RTS serial interface they provide for the positive supply via diodes D1 and D2. This voltage is unregulated, is the positive power of the input stage. By cons, it is regulated to 5 volts through IC2 so that it feeds a voltage very stable MIC 640.
As the current and available for both the positive supply for the negative supply is still low (10 mA max), I had to carefully choose the components used and they will not be replaced under any pretext. IC2 is indeed a regulator 5 volts 3 feet very low: in one case in 2936 SM Z5 which absorbs only 500 uA. For information, its "equivalent" the 78L05 consumes 3 mA in the same situation!
The input stage meanwhile was achieved using four operational amplifiers effect transistor field-mounted voltage followers. This confers to the module input impedance greater than 100 MW. All four amplifiers are combined in one box, referenced LF 444 at National Semiconductor, whose total consumption does not exceed 800 uA for the four amplifiers! Again, no question of putting such a TL 084 which face voracious with its 5.6 mA!
This input stage is protected from excessive voltages through resistors R7 to R10 and diodes D6 to D13. If you precede the various stages of converting physical quantities / voltage, you can possibly do without protection diodes that degrade somewhat the very high input impedance of 444 MQ due to their leakage current. It is in fact only 50 pA maximum input of 444 LF while a diode, even small leaks, easily misses 1 nA or 20 times more!
Tuesday, November 16, 2010
Portable Amplifier based on TEA2025
This is the diagram of simple portable amplifier circuit. This amplifier circuit build based on IC TEA2025 that is a monolithic integrated audio amplifier of 16-pin plastic dual in line package built by UTC manufacture. The circuit has an internal thermal protection. The circuit designed for portable cassette players and radios. You can also use as PC audio amplifier.
Here the amplifier diagram for stereo audio input/output:
and here the amplifier with mono audio input/output (bridge):
Stereo per channel
VCC=9V; RL=4 ohm/3W
VCC=9V; RL=8 ohm/2W
Bridge Application
VCC=9V; RL=8 ohm/5W
VCC=9V; RL=4 ohm/8W
Supply Voltage min = DC3v @ 500mA
Supply Voltage max = DC12v @ 500mA
Supply Voltage recommended = DC9v @500mA
Download TEA2025 Datasheet
Download the schematic diagram in PDF format HERE
Monday, November 8, 2010
Guitar Amplifier Circuit Diagram 100W
The ability amp lath has remained banausic back it was aboriginal appear in 2002. It absolutely isn’t broken, so there’s no acumen to fix it. The photo beneath shows a absolutely accumulated lath (available as apparent as M27). Application TIP35/36C transistors, the achievement date is advisedly massive overkill. This ensures believability beneath the best backbreaking date conditions. No amplifier can be fabricated allowed from everything, but this does appear close.
The ability amp (like the antecedent version) is about based on the 60 Watt amp ahead appear (Project 03), but it has added accretion to bout the preamp. Other modifications accommodate the abbreviate ambit aegis – the two little groups of apparatus abutting to the bent diodes (D2 and D3). This new adaptation is not massively altered from the original, but has adjustable bias, and is advised to accommodate a “constant current” (i.e. aerial impedance) achievement to the speakers – this is accomplished application R23 and R26. Note that with this arrangement, the accretion will change depending on the amount impedance, with lower impedances giving lower ability amp gain. This is not a problem, so may cautiously be ignored.
Should the achievement be shorted, the connected accepted achievement appropriate will accommodate an antecedent akin of protection, but is not absolutely foolproof. The abbreviate ambit aegis will absolute the achievement accepted to a almost safe level, but a abiding abbreviate will account the achievement transistors to abort if the amp is apprenticed hard. The aegis is advised not to accomplish beneath accustomed conditions, but will absolute the aiguille achievement accepted to about 8.5 Amps. Beneath these conditions, the centralized fuses (or the achievement transistors) will apparently draft if the abbreviate is not detected in time.