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Solid state relays are almost everywhere these days, but they are very expensive. So, your efforts to build their own salary. Especially since it’s only a few parts and circuit simple and straightforward. Solid state relay is not really at all relays. There are no “relay” is available only with electronics, connection works. It works well as a relay, you can use low voltage higher and better. “Relay” between 115/220V AC wires in place, although it was customary, the neutral conductor and leave unchanged phases and neutral. As long as no voltage (left in picture), the phototransistor TIL111 blocks of energy, and thus is not available. To ensure that the base TIL111 is fed to the transmitter (s) through the 1M resistor. This method prevents the base of transistor BC547B will be low and remains biased ‘on’. Collector is low and the gate (g) TIC106M thyristor, which is still in the country, “off”. 4-diode bridge rectifier circuit has no power apart from a small base and collector current B...

Triangular Wave Oscillator Circuit Diagram . This design resulted from the need for a partial replacement of the well-known 8038 chip,  which is no longer in production and there fore hardly obtainable.  An existing design for driving an LVDT sensor (Linear Variable Differential Transformer),  where the 8038 was used as a variable sine  wave oscillator, had to be modernised. It may  have been possible to replace the 8038 with an  Exar 2206, except that this chip couldn’t be used  with the supply voltage used. For this reason we  looked for a replacement using standard components, which should always be available. In this circuit two opamps from a TL074 (IC1.A  and B) are used to generate a triangular wave,  which can be set to a wide range of frequencies using P1. The following differential amplifier using T1 and T2 is configured in such a way  that the triangular waveform is converted into  a reasonably looking sinusoidal wavefo...

This is a simple project of 2-Wire Temperature Sensor Circuit Diagram. The Type LM35 temperature sensor from National Semiconductor is very popular for two reasons: it produces an output voltage that is directly proportional to the measured temperature in degrees Celsius, and it enables temperatures below zero to be measured. A drawback of the device is, however, that in its standard application circuit it needs to be connected to the actual measuring circuit via a three-wire link. This drawback is neatly negated by the present circuit. When the LM35 is connected as shown, a two-wire link for the measurement range of –5 °C to +40 °C becomes possible. 2-Wire Temperature Sensor Circuit Diagram:     Two-Wire Temperature Sensor Circuit Diagram Actually, the circuit shown is a temperature-dependent current source, since it uses the variation of the quiescent current with changes in temperature. The values of resistors R3 and R4 are calculated to give an output voltage of 10mV °C–1....

One type of metal detector is a type of beat frequency oscillator (BFO). The methods used in metal detectors in general are changing the characteristics of the oscillator when there are close to the metal sensor. The detector works based on the resonant frequency that has been set change when there is a metal object is located quite close to the search coil sensors. Tuning circuit (tuned circuit) should be a part of our oscillator circuit so that if approached by a metal coil sensor specific hence the output frequency of the oscillation circuit is about to change. Variation changes the output frequency depends on the frequency chosen. The selection of the higher frequency will cause the circuit sensitivity increases because the greater the frequency change. Stay if the selection frequency is too high then the practice will produce a system that is not sensitive. This is because the high frequency of most will not be reflected back but will be absorbed by the soil, building materials. M...

This is the Simple Two 555 Timers Bell Circuit Diagram. This simple scheme uses two Bell 555 timer. The frequency controlled capacitors, which should be preserved are almost identical in value with each other to achieve the best results. Fine tuning is done with the R1 and R2. The decay time is controlled by R3.[ ] Simple Two 555 Timers Bell Circuit Diagram

This small circuit was developed to monitor the battery in a model hovercraft. The lift in the model is produced by an electric motor driving a fan. To avoid the possibility of discharging the rechargeable battery pack too deeply, the design lights a conspicuous LED mounted on the model when a preset threshold voltage is reached. The circuit only uses a few components, which helps keep the total weight of the model down. The circuit connects to the model only across the two points where the voltage to be monitored can be measured. These also supply power to the circuit. The best place to connect the circuit is not at the battery terminals, but rather at the motor connections. The circuit is suitable for use with nominal battery voltages of 4.8 V to 9.6 V (four to eight 1.2 V cells). For example, if there are six cells in the battery, its nominal terminal voltage will be 7.2 V. A discharge threshold voltage of around 1 V per cell is appropriate, which means that for six cells the thresh...

Build a BTL Stereo Amplifier Circuit Diagram with TDA7052 , you can see circuit and start make a BTL Stereo Amplifier Circuit Diagram with TDA7052. BTL Stereo Amplifier Circuit Diagram with TDA7052 

Description: The NTE1373 is an integrated circuit designed for use as a 7.5W (16W, 4Ω) power amplifier output  with low noise and low distortion suitable for TV sets with multi−sound.  Stereo operation is possible due to incorporating two amplifiers on one 12−Lead SIP type chip. Features: Built−In Protection Circuits (Surge, Thermal Protection, etc.) Automatic Operating Point Stabilizer Circuit Low Distortion, Low 1/f Noise Low Shock Noise from Power ON/OFF Operation Better Channel Separation Few External Components Required

Here is a very simple and easy to use audio amplifier using I.C BEL (Bharat electronics limited)1895 , a very common IC. This circuit can run on 3V to 6v , making it easy to use in pocket amplifier . Cost is under 25/- Parts list: BEL1895 I.C (DIP8), C1 = 470uF/10V, C2 = 1000uF/16V, C3 = 220uF/10V, C4 = 100uF/10V, C5 = 4.7uF/10V, C6 = 47pF, C7,C8 = 1uF, R1 = 47Ohm, R2 = 470Ohm, R3 = 100K, R4 = 1Ohm, R5 = 10K V/C, speaker, etc… Total cost is around 20-30 rupeess(INR) or 0.6USD. 

There are some hopes that the sun will become a main source of energy in the 21st century. By then, sources of oil will be almost exhausted and will only play a minor part in the supplying of energy. Interested to know how to make a simple solar tracker with dual axis? Learn More The present interest in solar energy is therefore not surprising. Some work has already been done with solar cells and solar panels . However, these only operate with optimum performance when positioned exactly at right- angles to the sun. Unfortunately, this situation is not usual in our latitudes unless the solar panels are rotated with respect to the sun. The efficiency of a solar panel system can be improved if the panels track the sun, and remain as long as possible at the most favorable angle of incidence.  The circuitry required is relatively simple. lt uses a window comparator which keeps the drive motor idle, as long as the two LDrs are subjected to the same illumination. Half the operating v...

LA4446 is of similar series IC as LA4440, but it is meant for dual or stereo 5.5Watt RMS outputs. While 4440 gives 6Watt outputs at dual mode, this gives almost same but with much smaller package size. The IC package is mall but it provides same functionality and special features like LA4440. These are, Low pop noise at power ON/OFF time Good ripple rejection: 46dB(typ) Good channel separation Low residual noise (Rg=0) On chip protectors as Thermal protector, Over-voltage/Surge Protector, and pin short protector The below circuit is the application circuit of LA4446 IC. 

Here is a circuit to generate sequentially running light effects using a simple program written in C. The output of the program is taken from the LPT port of a PC and then fed to the interfacing circuit for the LED display. The outputs of the interfacing circuit are decoded, inverted, and then connected to LED s through optocouplers.   Fig. 1: Interfacing circuit for PC-driven LED display The interfacing circuit along with the 25-pin parallel port is shown in Fig. 1. IC1 (74LS138) is a high-speed 1-of-8 decoder/demultiplexer. In the circuit, only five outputs (pins 10 through 14) of IC1 are used. These outputs are inverted using  NOT gate IC2 (7404). Optocouplers IC3 through IC7 (MCT2E) are used to prevent the circuit from damage in the event of short circuit in the load.  Thus the loads comprising LED blocks LB1 through LB5 are isolated from the interfacing circuit including the PC. Each LED block contains a number of LED s connected in series. The LED s can be arrang...

This is the Simple Cathode led Display Circuit Diagram. Teledyne TSC7135 DVM chip is used to drive a multiplexed 5-digit display. A CD4513BE CMOS IC, for common cathode drive, is used as a segment driver selected by pins 17-20 of the DVM chip. The transistors can be any suitable npn type such as 2N3904, etc.  Simple Cathode led Display Circuit Diagram

The circuit was designed to provide distribution, extension and splitting of personal computer video output to two or more monitors. Super Video Graphics Array (SVGA) – defined in 1989 as a set of graphic standards that supports 800 X 400 resolution or 480,000 pixels with support for 256 colors or a palette of 16 million colors. Pixel – short for picture element, is the smallest point or single item of information in a graphic image and the basic unit of programmable color on a computer image or computer display. 2N3906 – a common PNP BJT transistor intended for medium voltage, lower current and power, which can operate at moderately high speeds, used for general purpose switching and low-power amplifying applications. The circuit may also be called as video port expander, multiple monitor, PC video splitter, LCD Y splitter, etc. It provides the same high resolution image to several monitors using a single PC. Each line of the SVGA card of the analog output stage of PC contains 75 ohm ...

A small electronic switch that connects a battery to the equipment for a certain amount of time when a push-button is momentarily pressed. And we have also taken the ambient light level into account; when it is dark you won’t be able to read the display so it is only logical to turn the switch off, even if the time delay hasn’t passed yet. The circuit is quite straightforward. For the actual switch we’re using a well-known MOSFET, the BS170. A MOSFET (T2 in the circuit) used in this configuration doesn’t need a current to make it conduct (just a voltage), which makes the circuit very efficient. When the battery is connected to the battery saver circuit for the first time, capacitor C2 provides the gate of the MOSFET with a positive voltage, which causes T2 to conduct and hence connect the load (on the 9 V output) to the battery (BT1). C2 is slowly charged up via R3 (i.e. the voltage across C2 increases). Battery Saver Circuit Diagram This causes the voltage at the gate to drop and eve...

This simple Telephone Record Control Circuit Diagram will allow you to connect any tape recorder that has a mic and remote input to a phone line and automatically record both sides of a conversation when ever the phone is in use. You will need to take a couple of voltage readings before connecting the circuit. First determine the polarity of your phone line and connect it to the circuit as shown and then determine the polarity of the remote input and connect it to the circuit. Circuit operation is as follows. When the phone is on hook the voltage across the phone line is about 48volts dc. When the phone is off hook the voltage will drop to below 10volts dc. When the line voltage is at 48volts the FET is off which causes Q2 and Q3 to be off. When the phone is picked up the FET turns on along with Q2 and Q3 which turns your recorder on. The tape recorder must be in the record mode at all times. As you can see the power source for the circuit is the phone line.  Telephone Record Con...

Green USB switch Circuit Diagram. According to the Energy Saving  Trust, if you add up all the current drawn in standby mode by items such as stereos, TVs, VCRs and DVDs over a year in the UK alone, it amounts to 3.1 million tonnes of CO2 released into the atmosphere.This is without factoring in the current drawn by all the PCs,laptops and their associated peripherals left in standby mode.  Green USB switch Circuit Diagram Green USB switch Circuit Diagram It  is  not  necessary  to  spend  a  great deal of money or time to  make a difference on a personal  level. The circuit described here  is designed for use by laptop or  notebook computers. It will automatically switch off all mains  powered peripheral equipment  including monitor, printer, scanner, TV tuner and USB hub etc  when it detects that the notebook  is switched off. The circuit is quite  straightforward; in addition to an  opto...

Basic Of Switch Mode Power Supply In recent years, the use of switch mode power supply (SMPS) has become more comon as more applications demand for greater power eficiency. It makes use of semiconductor (mostly MOSFET) fast switches to switch DC input that has been rectified at high frequency. The advantages of high frequency switching are that it reduces the size of inductor, capacitors & transformer used. Other advantages of switching power supply over linear power supply are : 1) High Efficiency (up to 90% and above for nice design). 2) Output can be higher than input. 3) Able to operate over a variety of input power supply. 4) Able to have over output. The setback of using SMPS compared to linear power supply is that it generates electrical noise which contributes to electromagnetic compatibility design issues & more part count. Buck Converter SMPS The SMPS circuit below from Power Integration makes use of LNK304 as its high frequency switch. Take note that this circuit is...

This is a simple Fly back Transformer Driver Circuit Diagram and an efficient flyback driver for modern cylindrical rectified television flybacks . Many sites doesn't provide circuits driving these transformers, they simply say that they are bad. I don't agree. In fact I built this circuit. I spent a lot of time for finding resonant frequency (around 15Khz) and duty cycle. These transformers best work at around 90% duty cycle. You may notice corona breakdown at terminals and pfffff sound (as well as the ozone smell) when adjusting the off time trimmer to near 500-300 ohms. Of course it will work for other tipes of flyback as frequency and duty cycle have a large range.  Flyback Transformer Driver Circuit Diagram Frequency range can be increased using multiposition switch for other values of C3 capacitor ,for example 2 nF for 80KHz-200000KHz, but didn't found flybacks with so high resonant frequencies, in addition with higher values of c3 , eg 200nF, 2uF the frequency will ...

Here is a remote operated spy robot circuit which can be controlled by using a wireless remote controller. It can capture audio and video information’s from the surroundings and can be sent to a remote station through RF signals. The maximum range is 125 meters. It overcomes the limited range of infrared remote controllers. This robot consists of mainly two sections. They are explained in detail below. Remote Control Operated Spy Robot Circuit – Block Diagram Remote Control Operated Spy Robot Circuit - Block Diagram 1. Remote Control Section The circuit uses HT 12E, HT 12D encoder and decoder. 433MHz ASK transmitter and receiver is used for the remote control. H-bridge circuits are used for driving motors. Two 12V DC/100RPM gear motors are used as drivers. The working of the circuit is as follows. When we are pressing any key in remote controller the HT 12E generate 8 bit address and 4 bit data .The DIP switches are used for setting the address. Then the ASK transmitter sends the 8 bi...