LED photo sensor circuit

Using a common benefit of photovoltaics LED, the circuit can recognize a different output darkness and light.

This circuit is used J-FET for recieve signal to buffer from LED ,About Output voltage,We used IC 1458 or LM1458 , while in the dark is about 7 volts and the drop about 2 volts in full sun. The LED voltage buffered by a junction FET transistor and then applied to the input of an operational inverting amplifier with a gain of about 20 minutes. This is a variation of about 5 volts of darkness and light. You can adjust the 100K potentiometer to set the range of output voltage.

surround sound circuit

This system uses the front and rear with three or more channels to create directional sound sources and the surrounding envelope of sound. It can be digital or analog as the term is widely used for the introduction of home theater systems in recent years. The surround sound system includes a variety of ways in which a sound source is enhanced by the quality of audio playback with the addition of speakers by discrete audio channels.

Part List
All capacitor = 10 uF
All Resistor = 1k ohm
Op amps 741 ,1458(dual op amp) may be used

The purpose of the construction of this circuit is to provide a decoding scheme using the surround sound system and is not intended to replace the surround sound decoder available on the market because they contain different features and functions. The circuit, however, can be used with other basic features as a standard decoder. Early versions of Dolby Digital have been eliminated and replaced with Dolby 5.1, DTS and other versions of success that support the transport layer and managing digital audio signals. The basic process requires four channels Dolby Surround information center, rear, front left and right surround contained in a signal of two channels. The decoding of the four channels is made possible by a decoder chip that sends a signal to the appropriate destination.

Dolby Digital is a trademark of technologies developed by Dolby Laboratories for a number of loss audio compression where the compression and decompression of data results in a production that is characteristic of the original, but still useful in some way. Dolby Digital can be done in mono, 2 channel, 4 channel, 5.1 channels or 6.1 channels. However, it must be remembered that the term Dolby Digital does not refer to the number of channels it contains, but on the digitally encoded audio signal. Although Dolby 5.1 and 6.1 is often referred to simply as Dolby Digital, in most typical applications.

To enable its spread in many directions, Dolby Digital 5.1 is the addition of stereo rear surround that make them more accurate and more flexible. They can also provide greater importance to the effects of low frequency with the addition of a dedicated subwoofer channel. Encoding and decoding of Dolby Digital requires the same amount of frequency range and power, as the main channels as opposed to Dolby Pro Logic where there is a limited frequency response and only minimal power to the rear channel.

Other versions of Dolby Digital Dolby Digital EX are as follows, using the matrix technology with the addition of a single rear surround channel stereo tracks and a center channel and functions as its predecessor, Pro Logic, Dolby Digital Surround EX, which provides support for 5.1 soundtracks that is compatible and cheap way for a center rear surround channel for best results localized, and Dolby Digital Live (DDL) which is used for interactive media such as video games such as real-time hardware encoding to convert any audio signal from a game console in 5.1-channel Dolby Digital and the transfer by a Sony / Philips Digital Interconnect Format (S / PDIF) Dolby Digital Plus offers increased throughput, the improved coding techniques to reduce compression artifacts, compatibility with existing, and support for more audio channels and Dolby TrueHD is a lossless audio codec that supports advanced support the necessary codecs for HD DVD.

The operation of the circuits from over transportation in stereo surround information on the audio signal from the main volume of the circuit. This allows for the left channel Lch attached to the model TL072 IC1A IC1b and which is attached right channel UC. The outputs of these operational amplifiers used as input buffer for the subsequent stages of the circuit. IC2C is responsible for the synthesis of signals from left and right channels that feed the output of center speaker while IC2D is responsible for the increase of the phase difference between left and right channels which is encoded into two channels and will be introduced into the rear speakers. We must ensure that the negative terminal of rear speaker is not simply because the ground in parallel with the main speakers.

The output of delay unit power IC2D regulated its rear speakers. This would create the sense of spacing depending on the size of the room. This will integrate its op-amp signal delay IC5 MN3004 has 512 levels. Since IC4 MN3101 is a clock signal, provides time IC5 as it functions as an oscillator in the circuit. Variable capacitor C17 sets the time delay in the circuit. The presence of filters in the circuit is to keep the noise to be generated during the process. These filters can be set to reduce rates by more than 8 kHz and below 100 Hz, to be able to drive the rear speaker. The rear diffuser is low because its input is encoded with a bandwidth of 100 Hz to 8 kHz. The filters are built around the IC6A / B which is also an output buffer. A potentiometer is placed in each output to aid in the control and regulation of speakers and amplifiers. The power supplied to the circuit is 15 V and each output can drive a single power amplifier.

condenser mic preamp circuit

Here is the schematic circuit diagram for electret condenser microphone amplifier. using a LM1458 dual op amp Operational Amplifier IC. electret condenser microphone by bias circuit and preamp

The circuit takes the audio signal rom the condenser microphone and amplifier it, so you can use the microphone as the input to some device which wouldn’t normally accept microphone level signals (which are very low).

This amplifier has an adjustable gain, which is performed via. R1 (a 1 Mega Ohm variable resistor). It controls the feedback of the LM1458 dual opamp, which in turn drive a LM1458 output IC.

Electronic Parts List:
Q1,Q2 – LM1458 transistor
R1,R2,R3 – 4.7k ohm resistor
R4, R5 – 10k ohm resistor
R6,R7 – 47k ohm resistor
C1, – 0.22uF ceramic capacitor
C2, – 1uF ceramic capacitor

MIC1 – electret condenser microphone
All resistors are 5 or 10 percent tolerance, 1/4-watt. All capacitors are 10 percent tolerance, rated 35 volts or higher.

AC current detection circuit

This circuit will detect power line currents of 250 mA or more without making electrical connections to the line. Current is detected by passing a line of alternating current through an inductive pickup (L1) as a screen diameter of 1 inch U-bolt wound with 800 turns # 30 – # 35 magnet wire.

The pickup could be made from rings of iron or other type of processor core that allows enough space to pass one of the AC lines through the center. Only one of the power line is the line or neutral must come from the center of the pickup to avoid the fields cancel.

I tested the circuit with a 2 wire extension cord that had separated the twin wires a small distance with an exacto knife to allow the U-bolt to encircle a single cable. The magnetic pick-up (U-bolt) produces about 4 millivolts peak for a series of alternating current of 250 mA, or AC load of around 30 watt.

The signal from the pickup has grown about 200 times the output of pin op-amp 7, followed by the peak detected by diode and capacitor connected to pin 7. The second op-amp used as a reference point, which detects voltage increases above the drop pass.

The minimum mark required to cause the comparator output stage is a positive change of 800 mV peak around a power line 30-watt. The 1458 swing op-amp output in just a couple of times the ground so a voltage divider (1K/470) is used to reduce the voltage signal at about 0,7 volt.

An additional diode added in series with transistor base to ensure that off when the voltage op-amp is 2 volts. You can get a piece “of relay chatter if the AC load is close to the switching point so a larger load 50 W or higher recommended. The sensitivity can be increased by adding more becomes a pick-up.

18-36 power control

This power supply circuit is adjustable 18-36 volts and is currently shown as being limited to 2 amps, but up to 3 amps in a small current sense resistor of Options (0.3 ohm). 2N3055 and 2N3053 transistors should be in wells. very hot right now and resistance is to be made at 3 watts or more. Voltage, which is controlled by 1 / 2 of the LM1458 Op Amp, or 1458-AMP. It can be replaced in the circuit below, but sources indicate pressure. Pin 8 to 30 VDC supply is limited, which may increase by 6.2 Vdc or 5.1 Vdc. Zener K-series resistance, is 8-pin. Maximum supply voltage DC for LM1458 and LM1558 are 36 and 44, respectively.

    Should be the power transformer. As expected the power supply. Enter at least 4 times the desired output voltage, but can not exceed the op-amp under conditions of low stress. Transformer is used as a center, see 25.2 volts AC / AMP 2 units to regulate the 24 volts at 0.7 amps, 15 volts at 2 amps or 6 volts at 3 amps. Output AMP 3 is the center of the water. Transformer that changes the position of 18 volts. All components must be an exception from Radio Shack LM1458 op-amp.