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This is the project of Digital Fan Regulator Circuit diagram. The circuit presented here can be used to control the speed of  fans using induction motor. The speed control is nonlinear, i.e. in steps. The current step number is displayed on a 7-segment display. Speed can be varied over a wide range because the circuit can alter the voltage applied to the fan motor from 130V to 230V RMS in a maximum of seven steps.  The triac used in the final stage is fired at different angles to get different voltage outputs by applying short-dura-tion current pulses at its gate. For this pur-pose a UJT relax-ation oscillator is used that outputs sawtooth waveform. This waveform is coupled to the gate of the triac through an optocoupler (MOC3011) that has a triac driver output stage.  Pedestal voltage control is used for varying the firing angle of the triac. The power supply for the relaxation oscillator is derived from the rectified mains via 10-kilo-ohm, 10W series dropping/limit-ing...

This automotive electronic project simple but digital pressure gauge circuit. Using an intersil ICL 7106 A/D converter chip and an LED display module, this gauge uses a Sensym Corp. Digital Pressure Gauge Circuit Diagram: Pressure transducer SXlOOpn (100 psi full scale) in a Wheatstone bridge configuration to drive an op amp (ICla, b, c) translator circuit that supplies a dc voltage to IC2 that is proportional to pressure. R6 sets the gain of IC1A (full-scale sensitivity) and R16 supplies a zero adjustment. IC3 provides regulated + 5 V to power the circuit.

Circuit Diagram 1 Circuit Diagram 2   Circuit Diagram 3 Description Even if the digital multimeters have dominated in a lot of applications, in the measurement, exist the need for existence of instruments of clue in various appliances, voltage and current, as in power supply or elsewhere. The circuits that give make this precisely the work, measure the voltage in terminal a circuit and the current that passes in his. The circuit does not present particular difficulties for somebody that has a small experience. The two circuits are the himself, with a small difference only in their input, when they have they measure voltage or current and in connection that concern decimal point [ dp ]. In the department of input IC1 and IC3, exist the CA3161E, that is a A/D Converter for 3-Digit Display. In the drive of Display IC2 and IC4, exist CA3161E, that is a BCD the Seven Segment Decoder/ Driver. As it appear in Fig.1, that concern the voltmeter in input [ + IN ], exist in series a what resi...

This Digital Mains Voltage Indicator Circuit diagram project designed by  Pratap Chandra Sahu . Continuous monitoring of the mains voltage is required in many ap-plications such as manual volt-age stabilisers and motor pumps. An ana-logue voltmeter, though cheap, has many disadvantages as it has moving parts and is sensitive to vibrations. The solidstate voltmeter circuit described here indicates the mains voltage with a resolution that is comparable to that of a general-pur-pose analogue voltmeter. The status of the mains voltage is available in the form of an LED bar graph. Presets VR1 through VR16 are used to set the DC voltages corresponding to the 16 voltage levels over the 50-250V range as marked on LED1 through LED16, respectively, in the figure. The LED bar graph is multiplexed from the bottom to the top with the help of ICs CD4067B (16-channel multiplexer) and CD4029B (counter). The counter clocked by NE555 timer-based astable multivibrator generates 4-bit binary ad-dress...

Description counter 0-9 This counter 0-9 in easy to assemble, basic to use for other more complex where we make use of integrated circuits didactically as these could be replaced by other more complex circuits with simple application of microcontrollers. Counter operation 0-9. This counter circuit is formed by a generator essentially comprises a wave 555 which functions as a circuit astable multivibrator operating this type is characterized by an output square waveform with width defined by the designer.The outgoing wave frequency can be controlled by the resistor is connected between pins 7-8 and 2-7 in addition to the electrolytic capacitor connected to pin 2 of land. The pulse output can be varied by 100K ohm potentiometer (RV1). Circuit counter The 7490 is a counter asynchronous decades BCD to binary, this counter counts the falling edges of the clock pulses generated by 555, 4 outputs move counter to count in binary 0 in BCD (0000) to 9 BCD (1001). To counter operation must co...

Theremin circuit shown in this schematic diagram uses digital component, so we can call it a digital Theremin. This circuit employs  logic inverter 74C04 or CD4069 hex inverter and CD4046 phase-locked-loop (PLL) IC.  The CD4069 logic inverter is operated as a fixed-frequency oscillator with  frequency around 100kHz. The CD4046 is operated as a variable frequency oscillator which is adjustable around 100kHz. The exact center frequency of the on-chip oscillator is determined by R4, C2 and R3. Here is the schematic diagram of the circuit.  Digital Theremin Circuit Diagram The frequency of variable oscillator frequency circuit can be shifted several kilohertz by moving your hand approaching the antenna since the C2 and the antenna form an equivalent parallel capacitance. The frequency of the variable oscillator should be set to the same frequency of fixed oscillator when there is no hand or human body close to the antenna.  This  calibration is done by adjustin...

Today I'll introduce you how to make a simple digital watch with LCD 16x2 and PIC 16F877a. It's very easy to implement this clock and you can make this as a gift clocks for kids. I'll also provide you the source code of the clock so you can easily customize to make your own countdown clock, count up timer or something that more useful than an analog clock. OK. Below is the circuit diagram of the digital watch. Online Digital Clock Circuit Diagram SOURCE CODE: Tags:  digital clock online,  555 timer,  count up timer,  a timer,  555 timer projects,  digital wall clock,  Note : If you have any problem with running this code, feel free to comment below. This project has 2 file as described below. Copy it to your workspace, compile and run. File: LCD4bit.h #define lcd_RS PIN_D1 #define lcd_RW PIN_D2 #define lcd_E PIN_D3 #define lcd_B1 PIN_D4 #define lcd_B2 PIN_D5 #define lcd_B3 PIN_D6 #define lcd_B4 PIN_D7 #define dong_1 0x80 #define dong_2 0...

This circuit is a Digital Radar Speedometer. It allows us to evaluate the speed of any object moving, especially cars and other vehicles. The speed is calculated in kilometers per hour (KPH). Its display has three digits. This radar works with the laser reflexion. It sends laser radiation to the object and this object reflects the laser radiation to the radar. To evaluate the speed of a vehicle, we must be in front of it. In other words, the vehicle must come in our direction. The front of the radar must point the front of the vehicle. The radar has the shape of a pistol. In this radar, it has a laser LED and a laser diode. Both have a lens. Digital Radar Speedometer Circuit Diagram The laser LED can send a spot of light to a distance of 90 m (295 ft). It's very important that the distance range of the laser LED is 90 m, if not, the speed will not be calculated properly. The laser diode, which receives the light signal by the laser LED, must be able to detect the light which is sam...

This digital SP tachometer for bikes uses 2 reed switches to urge the speed data of the bicycle. The reed switches are put in close to the rim of the wheel where permanent magnets pass by. The permanent magnets are connected to the wheelspokes and activate the reed switches everytime they pass by it. The speed is digitally displayed. The tachometer circuit works in step with this principle; the pulses created by the reed contacts are counted inside an explicit time interval. The ensuing count is then displayed and represents the speed of the bike. 2 4026 ICs are used to count the pulses, decode the counter and management 2 7-segment LED show. RS flip-flops U3 and U4 perform as anti-bounce. Electronic bicycle SP tachometer circuit diagram The pulses arrive at the counter’s input through gate U7. The measuring amount is set by monostable multivibrator U5/U6 and might be adjusted through potentiometer P1 so the tacho are often calibrated. The circuit U1/U2 resets the counters. Since batte...

Circuit Diagram Description This circuit is a Digital Radar Speedometer. It allows us to evaluate the speed of any object moving, especially cars and other vehicles. The speed is calculated in kilometers per hour (KPH). Its display has three digits. This radar works with the laser reflexion. It sends laser radiation to the object and this object reflects the laser radiation to the radar. To evaluate the speed of a vehicle, we must be in front of it. In other words, the vehicle must come in our direction. The front of the radar must point the front of the vehicle. The radar has the shape of a pistol. In this radar, it has a laser LED and a laser diode. Both have a lens. The laser LED can send a spot of light to a distance of 90 m (295 ft). It's very important that the distance range of the laser LED is 90 m, if not, the speed will not be calculated properly. The laser diode, which receives the light signal by the laser LED, must be able to detect the light which is same color as tha...

This digital thermometer circuit diagram uses a common 1N4148 diode as the temperature sensor. The temperature coefficient of the diode, -2 mV / 0C is exploited for this application to create an accurate electronic thermometer. To display the measured temperature, a digital multimeter is used and so we can measure temperature values from -9.990C up to +99.90C.   Calibration of the digital thermometer To set the minimum level (00C), place the diode in a glass of water filled with crushed ice (check the temperature first with a normal thermometer) wait until the thermometer shows zero degrees centigrade. Set P1 so that the digital voltmeter will display 000 when the diode senses zero degree centigade. To set the maximum level (1000C), place the diode sensor into a boiling water and adjust P2 so that the digital meter exactly displays 99.9. source [link] 

Digital Step-Km Counter Circuit Diagram. This circuit measures the distance covered during a walk. Hardware is located in a small box slipped in pants' pocket and the display is conceived in the following manner: the leftmost display D2 (the most significant digit) shows 0 to 9 Km. and its dot is always on to separate Km. from hm. The rightmost display D1 (the least significant digit) shows hundreds meters and its dot illuminates after every 50 meters of walking. A beeper (excusable), signals each count unit, occurring every two steps. A normal step was calculated to span around 78 centimeters, thus the LED signaling 50 meters illuminates after 64 steps (or 32 operations of the mercury switch), the display indicates 100 meters after 128 steps and so on. For low battery consumption the display illuminates only on request, pushing on P2. Accidental reset of the counters is avoided because to reset the circuit both push buttons must be operated together. Obviously, this is not a preci...

This digital thermometer circuit diagram uses a common 1N4148 diode as the temperature sensor. The temperature coefficient of the diode, -2 mV / 0C is exploited for this application to create an accurate electronic thermometer. To display the measured temperature, a digital multimeter is used and so we can measure temperature values from -9.990C up to +99.90C.   Calibration of the digital thermometer To set the minimum level (00C), place the diode in a glass of water filled with crushed ice (check the temperature first with a normal thermometer) wait until the thermometer shows zero degrees centigrade. Set P1 so that the digital voltmeter will display 000 when the diode senses zero degree centigade. To set the maximum level (1000C), place the diode sensor into a boiling water and adjust P2 so that the digital meter exactly displays 99.9. source [link] 

Description This circuit is a circuit diagram? digital voltmeterwith LED display. It’s ideal to use for measuring the output voltage of your DC power supply. It includes a 3.5-digit LED display with a negative voltage indicator. It measures DC voltages from 0 to 199.9V with a resolution of 0.1V. The voltmeter is based on single ICL7107  chip and may be fitted on a small 3cm x 7cm printed circuit board. The circuit should be supplied with a 5V voltage supply and consumes only around 25mA. The use of 7805 5V voltage regulator is highly recommended to prevent the damage of ICL7107, 555 ICs and to extend the operating voltages. The following is a schematic drawing: Parts list of The Digital LED Voltmeter: R1 = 8K2 R1 = 8K2 R2 = 47K / 470K R2 = 47k / 470K R3 = 100K R3 = 100K R4 = 2K R4 = 2K R5, R6 = 47K R5, R6 = 47k R7 = 0R / 4K7 R7 = 0R / 4K7 R8 = 560R R8 = 560R C1,C5, C6, C8, C9 = 100n C1, C5, C6, C8, C9 = 100n C2 = 470n / 47n C2 = 470n / 47n C3 = 220n C3 = 220n C4 = 100p C4 = 10...

Continuous monitoring of the mains voltage is required in many applications such as manual voltage stabilisers and motor pumps. An analogue voltmeter, though cheap, has many disadvantages as it has moving parts and is sensitive to vibrations. The solidstate voltmeter circuit described here indicates the mains voltage with a resolution that is comparable to that of a general-purpose analogue voltmeter. The status of the mains voltage is available in the form of an LED bar graph. Presets VR1 through VR16 are used to set the DC voltages corresponding to the 16 voltage levels over the 50-250V range as marked on LED1 through LED16, respectively, in the figure. The LED bar graph is multiplexed from the bottom to the top with the help of ICs CD4067B (16-channel multiplexer) and CD4029B (counter). The counter clocked by NE555 timer-based astable multivibrator generates 4-bit binary address for multiplexer-demultiplexer pair of CD4067B and CD4514B. The voltage from the wipers of presets are mul...

Digital Thermometer 0-100.0°C is a digital thermometer that operates in modetemperature measurement in Celsius (° C). Digital Thermometer 0-100.0 ° C in this article uses data processor in the form of a microcontroller AT89C4051. Temperature sensors used in Digital Thermometer 0-100.0 ° C. This temperature sensor LM35D. Digital Thermometer 0-100.0 ° C. It uses the temperature measurement data viewer in the form of 1 line LCD viewer. Digital Thermometer 0-100.0 ° C. It can display the temperature measurement data with a resolution of 0.1 ° C. Digital Thermometer Circuit Diagram Digital Thermometer 0-100.0 ° C. These temperature sensors make use of LM35D as temperature sensing. In Digital Thermometer 0-100.0 ° C. This temperature sensor measurement data this LM35D (Level Voltage) is then converted into 4-bit binary data using the ADC CA3162. Then the 4-bit data from ADC CA3162 which is a measurement of data if the temperature is in the AT89C4951 microcontroller so that it becomes an oper...

This digital DIY tachometer for bikes uses two reed switches to get the speed information of the bicycle. The reed switches are installed near the rim of the wheel where permanent magnets pass by. The permanent magnets are attached to the wheelspokes and activate the reed switches everytime they pass by it. The speed is digitally displayed. The tachometer circuit works according to this principle; the pulses created by the reed contacts are counted within a certain time interval. The resulting count is then displayed and represents the speed of the bike. Two 4026 ICs are used to count the pulses, decode the counter and control two 7-segment LED display. RS flip-flops U3 and U4 function as anti-bounce. Electronic bicycle DIY tachometer Circuit diagram: The pulses arrive at the counter’s input through gate U7. The measuring period is determined by monostable multivibrator U5/U6 and can be adjusted through potentiometer P1 so that the tacho can be calibrated. The circuit U1/U2 resets the ...

Digital visitor counter is a reliable circuit that takes over the task of counting Number of Persons/ Visitors in the Room very Accurately. When somebody enters into the Room then the Counter is Incremented by one and when any one leaves the room then the Counter is Decremented by One. The total number of Persons inside the Room is displayed on the seven segment displays.The microcontroller do the above job it receives the signals from the sensors, and this signals operated under the control of software which is stored in ROM. Digital visitor counter Digital visitor counter

Build a Simple Digital Electronic Lock Circuit Diagram . This is a Build a Simple Digital Electronic Lock Circuit Diagram . The digital lock shown below uses 4 common logic ICs to allow controlling a relay by entering a 4 digit number on a keypad. The first 4 outputs from the CD4017 decade counter (pins 3,2,4,7) are gated together with 4 digits from a keypad so that as the keys are depressed in the correct order, the counter will advance. Simple Digital Electronic Lock Circuit Diagram As each correct key is pressed, a low level appears at the output of the dual NAND gate producing a high level at the output of the 8 input NAND at pin 13. The momentary high level from pin 13 activates a one shot circuit which applies an approximate 80 millisecond positive going pulse to the clock line (pin 14) of the decade counter which advances it one count on the rising edge. A second monostable, one shot circuit is used to generate an approximate 40 millisecond positive going pulse which is applied...

This is a Digital Complementary metal–oxide–semiconductor (CMOS) logic Probe Circuit Diagram.The logic probe can indicate four input states, as follows: floating input—all LEDs off logic 0 input— D2 switched on (D3 will briefly flash on); logic 1 input— Dl_ switched on; pulsing input—D3 switched on, or pulsing in the case of a low frequency input signal (one or both of the other indicators will switch on, showing if one input state predominates). Digital Cmos logic Probe Circuit Diagram