Tuesday, September 9, 2014
BC550 Universal Audio Amplifier
A line amplifier is always a useful unit to have around, whether it is for matching a line signal or raising its level somewhat. This might be needed during a recording session or with a public-address system. Furthermore, a line mixer can be constructed from a number of these amplifiers. The input of the amplifier is high-voltage proof. The output impedance is low. The circuit is a conventional design: two dc-coupled stages of amplification are separated by a threefold Baxandall tone control system. The volume control at the input is conspicuous by having its `cold` side connected, not to ground, but to the output of the first amplifier. Because the signal there is out of phase with the input signal, the amplifier obtains negative feedback via PI. The amplification is therefore inversely proportional to the magnitude of the input signal. Thus, it is possible for the amplifier to accept a wide range of input levels. It is quite possible to input a signal taken directly from the loudspeaker terminals of a power amplifier. The supply voltage is 24 V. At that voltage, the amplifier draws a current of about 4 mA. If several amplifiers are used in conjunction (as, for instance, in a mixer panel), the various supplies (+ and + + in the diagram) can be interlinked. Capacitors C17 and C18, and resistor R7 don`t need to be duplicated in that case.
Sprint Layout Software
Simple but at the same time very efficient software package for designing and manual PCB layout small and medium difficulty.The program is very popular among Russian radio amateurs.
The main advantage of Sprint-Layout is a user-friendly interface, which includes only the necessary tools to prepare PCB size 300 x 300 mm.The program allows you to work with two layers (conductors and labeling) for each side of the board. Additional features - solder mask layer metallization, SMD-mask. Built tracer only helps raise guides, and is not automatic. In recharged library contains the most common electronic components. In Sprint-Layout implemented the ability to export your work in popular formats Excellon and Gerber, as well as create a HPGL file for finishing PCB on software-controlled milling machine. Package widely used to manufacture boards LUT method .
Program is unlikely to suit professionals, as its scope is limited by small boards with a low density of elements. But, thanks to logical and understandable structure, Sprint-Layout is very easy to learn and is recommended for beginners to designers who do not want to waste your time on the study of more complex programs.
Program Language German or English. Domestic enthusiasts was created fully functional Russified version of the program that gets the network name of Sprint-Layout 6 (however, had no relation to the official second version released in 2013). The interface has been redesigned for greater comfort, added a large number of electronic components and retain compatibility with all versions of the original Sprint-Layout to the fifth version.
The program runs stably in 32 - or 64-bit operating systems Windows 98 / ME / NT / 2000 / XP / Vista / Win 7
Simple Car Battery Voltage Monitor Circuit
A dual op amp is used as a comparator. The green LED on the board, until the voltage exceeds 11.5 volts. The red LED illuminates when the voltage falls below 11.9 volts to the schema. Therefore, in the 11.9 to 11.5 volts, both LEDs are on, producing a slightly yellow color. When the voltage falls below 11.5 V, the green LED, and now only the red LED flashes to indicate low voltage.
Parts List
R1=1K2R2-3-4=680R
R5=15K
R6=10K
R7-8-9-10=1K
IC1=LM324
D1=5V6 /0.5W Zener
D2-3-4-5=LED
RV1=10K trimmer
Is recommended that multi-shaper for V1 and V2. Muti-trimmer makes it much easier to trigger points to make as a less expensive single-turn trimmer. The trimmer can be completely eliminated if you have access to a range of 1% resistors and has had calculated carefully. You would also want to provide more accurate reference voltage as the common 78L05 regulator.
Light Switch Circuit Diagram
The series of light switches this time slightly different from the voltage of work. The series of light switches can work directly on the AC power network. Light switches are using the main component of TRIAC and LDR. The circuit is very simple and the components were sold in the market.
Read moreMonday, September 8, 2014
Headphone amplifier circuit
Headphone amplifier circuit with op amp ic OPA134, 2134, NE5532, 5534.
| Headphone amplifier circuit with op amp |
Overload Indicator TL072
The overload indicator consists of a window comparator that measures the magnitude of an a.f. signal. Two of the opamps contained in an TL072 are supplied with a reference voltage by potential divider R1-R2-R3-P1. The outputs of the opamps drive T1 via diodes D1 end D2 (that function as half-wave rectifier), which in turn actuates D3. Network R5-R6-C2 ensures that the LED lights even during short signal peaks. Capacitor C2 is charged fairly rapidly via D1 (or D2)and R5, after which it discharges slowly via R6, R9 and the base-emitter junction of T1. Capacitor C1 also contributes to the longer lighting of the LED.
. When the level of the signal at the input is high enough, IC1a, is toggled by the positive half periods of the signal and IC1b by the negative halves. In this way, a peak above the maximum level will be indicated even when the signal is asymmetrical. Because of the symmetrical power supply and design of the indicator, the reference voltage for both opamps can be set with one potentiometer. The circuit draws a current of 5-6 mA when the LED is off. When an overload peak is indicated, the LED draws an additional 20 mA. With values as shown, the reference voltage can be set roughly between 0.9 V and 5.5 V.
The circuit can be connected to the output of a power amplifier, but potential divider R7-R8 then needs to be adapted and protected by diodes to the supply lines.
Current Limiting Coil Driver circuit Wiring diagram
This is the Practical Current Limiting Coil Driver schema Diagram. The p-channel devices are switched off by current sensors when the coil current reaches 10 A. The operation is similar to that of a switching-type power supply. The Schottky diodes and resistors are for spike protection.
Current Limiting Coil Driver schema Diagram
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