Diagram IR Remote Control Circuit using Op amp 741

IR circuit is called Infrared Circuit. Remote controlsare
very much popular now-a-days. It is specially called cordless circuit.
This circuit is very simple and low cost cordless remote control circuit
which is based on infrared   rays.

Figure 1 shows thetransmitter circuit. The transmitter produces infrared rays and that can be easily transmitted up to 4 meters with a special convex lens and a twin LEDarrangements.

Figure 2 shows thereceiver circuit. Op amp IC1-741 generates high frequency squire wave which provides the gate pulses for SCR1. IC1’s output current flows through  SRC1 and it is conducting current and enables the LED to emits infrared rays. The output frequency of Op amp IC1 depends on the variable resistor VR1, which in turns varies the output radiations of the LED.

When IR rays
fall on the photo-transistor T1 of the receiver, then base of the
photo-transistor’s base produces charge carriers at a rate depending on
the rate of arrival of incident radiationsat
the pn junction of the transistor. Then the resulting emitter voltage
is amplified by Op amp IC-2 . The amplified signal is rectified by D2.
Finally the amplified signal is to drive the relay.

Parts List:

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IR Remote Control Tester

A 741 or LF351 will not work in this schema. Although I have used a 12 volt power supply, a 9 volt battery will also work here.






As I was developing my IR Extender Circuit, I needed to find a way of measuring the relative intensities of different Infra red light sources. This schema is the result of my research. I have used a photodiode, SFH2030 as an infra red sensor. A MOSFET opamp, CA3140 is used in the differential mode to amplify the pulses of current from the photodiode. LED1 is an ordinary coloured led which will light when IR radiation is being received. The output of the opamp, pin 6 may be connected to a multimeter set to read DC volts. Infra red remote control strengths can be compared by the meter reading, the higher the reading, the stronger the infra red light. I aimed different remote control at the sensor from about 1 meter away when comparing results. For every microamp of current through the photodiode, about 1 volt is produced at the output

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PWM Based Speed Control for DC Motors

There are several methods for controlling the speed of DC motors. One simple method is to add series resistance using a rheostat. As considerable power is consumed in the rheostat, this method is not economical. Another method is to use a series switch that can be closed/opened rapidly. This type of control is termed as chopper control. We’ve described here a PWM-based chopper schema that smoothly controls the speed of general-purpose DC motors.

Fig.1: Block diagram of PWM-based speed controller

Fig. 1 shows the block diagram of a basic PWM-based chopper. The schema shown in Fig. 2 is designed as per this diagram. A dual timer IC (NE556) is used to configure both the astable as well as the monostable multivibrator. Timing components for the astable are chosen to provide a frequency of 546 Hz, while the monostable components are selected to obtain a maximum pulsewidth of 2.42 ms. Diode D1 improves duty factor of the astable oscillator output, whereas D2 acts as a free-wheeling diode. Transistor SL100 drives the motor, while the 22-ohm, 2W resistor (R4) serves as a current limiter, avoiding overheating of the transistor. The DPDT switch enables direction reversal of the motor, as desired.

Fig. 2: The schema of PWM-based speed controller

The speed can be varied by adjusting VR1, which changes the threshold value to which capacitor C1 in the monostable schema is charged. This, in turn, determines its output pulsewidth and hence the average voltage applied to the motor. Waveforms shown in Fig. 3 depict the average voltage for controlling various speeds.

For effective speed control, ‘on’ period (TON) of the astable should be equal to the maximum pulsewidth (TON) of the monostable.

Fig. 3: Waveforms at different conditions of VR1

For higher voltage and power requirements, SL100 can be replaced by an appropriate MOSFET or IGBT with relevant changes in the drive schemary.

The schema costs around Rs 75.

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2005 Chevy Monte Carlo Body Control Wiring Diagram

2005 Chevy Monte Carlo Body Control Wiring Diagram

The part of 2005 Chevy Monte Carlo Wiring Diagram: body control module, ground distribution schematic, connector, battery, cruise control, engine coolant, power distribution schematics, junction block, courtesy lamp supply voltage, accessory voltage, battery positif voltage, ignition coil, keyless entry serial data, BCM class, DLC schematic in computer.

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How to Treble and Bass Control without IC or Transistor

This Treble and Bass Control without IC or Transistor schema consists of bass and treble just a few capacitors, resistors and two potentiometers to adjust BASS and TREBLE. The schema is very functional, can be used to adjust the small sound amplifiers. And control Treble and works relatively well. The interesting thing is that this control does not use or IC or transistor.

Treble and Bass Control without IC or Transistor Circuit Diagram

How to Treble and Bass Control without IC or Transistor

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