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400W Stereo Marshall Leach Amplifier

400W Stereo Audio Amplifier based on the original Marshall Leach involvement, but has made some improvements. Regarding the power supply voltage to the +-75V. VC comparing the performance of the modified Leach 700W/2R on one common board of both channels, as well as protection and control circuits for the fans. Compared to the 700W version a bit different in wiring. Because some things in the 700W version is completely tightened to perfection.                                                  700W version could criticize a couple of things: 1st very high gain output stage resulting in deterioration of signal noise distance. Therefore 700W version even more noisy. 2nd The absence of multipliers Ube bias current control and maintain temperature stability diagram. The 700W version of the thermal stabilization solved by a single transistor, which can sometimes cause a great loss due to power control is fast enough and has some delays. Therefore JPA400 added to this multiplier. 3rd Protectio
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Rolling Shutter Motor Control Circuits Diagram

An electrically operated rolling shutter usually has a standard control panel with a three-position switch: up, down and stop. If you would like to automate the opening and closing with a time controlled switch, a few additional wires will have to be connected. Typically, the controls are implemented as indicated in the schematic ‘Normal Situation’. If this is indeed the case, then you can see in ‘New Situation’ how the shutter can be automated with a timer. There is only one method to determine the actual schematic of your control circuit, and that is to open the control box and using an ohmmeter, pencil and paper to check out and draw the circuit. Make sure you turn the power off first though! Connect a 230-V relay (with both the contacts and the coil rated 230 VAC) to the timer.   The changeover switch between automatic and manual control needs to be rated 230 VAC as well and may not be a hazard for the user. The relay and switch are preferably fitted in a plastic mains adapter enclo
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Simple 6Meter kilowatt amplifier Circuit Diagram

This is the Simple 6Meter kilowatt amplifier Circuit Diagram.The amplifier uses a grounded grid circuit with either the Eimac 3CX1000A7 or 8877, ceramic/metal triodes intended for linear service in the HF and VHF ranges. The amp provides the legal power output of 1500 watts PEP and CW service with no effort and requires a driver delivering between 50 and 80 watts at 50 MHz. With a plate voltage of 3000 volts at 0.8 amps the amplifier performs at 60 percent efficiency. The grid is grounded by means of the grid ring of the 3CX1000A7 socket providing a low-inductance path td ground. The amplifier is completely stable. Simple 6Meter kilowatt amplifier Circuit Diagram
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Emergency Light using Phone Line Circuit Diagram

This is a circuit for emergency lighting with LEDs that uses electricity from the telephone line . Generally the phone line has a DC voltage 48V and somewhere around 20 mA , and when the phone rings , the voltage rises to 96V AC . This works in a way that the phone line will not be busy while the LEDs are turned on and when you pick up the phone , the light goes off and lets you use your phone normally .  Emergency Light using Phone Line Circuit Diagram
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Remote Control Blocker

This circuit was designed to block signals from infrared remote controls. This will prove very useful if your children have the tendency to switch channels all the time. It is also effective when your children aren’t permitted to watch TV as a punishment. Putting the TV on standby and put-ting the remote control out of action can be enough in this case. Circuit diagram : Remote Control Blocker Circuit Diagram The way in which we do this is very straightforward. Two IR LEDs continuously transmit infrared light with a frequency that can be set between 32 and 41 kHz. Most remote controls work at a frequency of 36 kHz or 38 kHz. The disruption of the remote control occurs as follows. The ‘automatic gain’ of the IR receiver in TVs, CD players, home cinema systems, etc. reduces the gain of the receiver due to the strong signal from the IR LEDs. Any IR signals from a remote control are then too weak to be detected by the receiver. Hence the equipment no longer ‘sees’ the remote control!
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INTRODUCTION TO TRANSISTORS

Hi friends...Today i am here with another article about transistor which is very important component of electronics.In this article i will discuss many topic regarding transistor and there uses..so lets start....... Introduction A semiconductor device with three connections, capable of amplification in addition to rectification. Transistors are used most widely used in most of the electronic projects and circuits. Transistors are used for amplification , like amplifying small current output of any logic IC to drive a lamp or relays etc. A transistor may be used as a switch (either fully on with maximum current, or fully off with no current) and as an amplifier (always partly on). The amount of current amplification is called the current gain, symbol hFE. Types There are two types of standard type of transistors , NPN and PNP, with different circuit symbols. The letters refer to the layers of semiconductor material used to make the transistor. Most transistors used today are NPN beca
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