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The electronic dog repellent circuit diagram below is a high output ultrasonic transmitter which is primarily intended to act as a dog and cat repeller, which can be used individuals to act as a deterrent against some animals. It should NOT be relied upon as a defence against aggressive dogs but it may help distract them or encourage them to go away and do not consider this as an electronic pest repeller. The ultrasonic dog repellant uses a standard 555 timer IC1 set up as an oscillator using a single RC network to give a 40 kHz square wave with equal mark/space ratio. This frequency is above the hearing threshold for humans but is known to be irritating frequency for dog and cats. Since the maximum current that a 555 timer can supply is 200mA an amplifier stage was required so a high-power H-bridge network was devised, formed by 4 transistors TR1 to TR4. A second timer IC2 forms a buffer amplifier that feeds one input of the H-bridge driver, with an inverted waveform to that of IC1 ou...

Programmer and Development Board from Extremeelectronics: Look at the below picture. The programmer I am using is bought from another manufacturer, not from extremeelectronics. It is an USB Porgrammer. You can get it from any leading electronics hobby electronics store. My programmer is not pin compatible with XboardMini which I brought from extremeelectronics. I modified the ISP connector for connecting the USB programmer with the board. The XboardMini does not has Vcc connection in its ISP connector. My programmer has Vcc connection in its ISP connection. 10th pin is free (not connected) in the Xboardmini ISP circuit. I modified my cable such that 9th pin gets Vcc from USB programmer. The red wire I connected goes from 10th pin to one of its Vcc node. In this way, the board directly gets Vcc from USB power supply. You dont have to use 9V adaptor for programming and powering the board. I dont know whether the usb programmer from extremeelectronics is having Vcc connection in its ISP P...

As previously mentioned (http://www.blogspot.com/2016/09/200000-views-ithaca-arm-and-dmips.html) I’m doing an independent study under the supervision of Professor Bruce Land here at Cornell University. A semester has passed and I will be continuing my independent study next semester. The independent study (that I'm doing and will be continuing) is on exploring and comparing the peripheral modules of the Microchip PIC32MX250F128B (on the Microstick II platform) and the Atmel AT91SAM3X8E (on the Arduino Due platform). This semester, I've done a good amount of introductory exploration of the two 32-bit microcontrollers. Here are the links to the datasheets of the two microcontrollers on which my independent study is based: AT91SAM3X8E: www.atmel.com/Images/doc11057.pdf PIC32MX250F128B: http://ww1.microchip.com/downloads/en/DeviceDoc/61168E.pdf The Microchip PIC32MX250F128B is a 32-bit RISC microcontroller based on the MIPS M4K core. In this independent study, I have used the Micro...

CASE STUDY, IMPLEMENTATION AND EXAMPLES OF I2C 1. ) I²C is a multi-master protocol that uses 2 signal lines. The two I²C signals are called ‘serial data’ (SDA) and ‘serial clock’ (SCL).The data rate has to be chosen between 100 kbps, 400 kbps and 3.4 Mbps, respectively called standard mode, fast mode and high speed mode.Each device can be a transmitter, a receiver or both. 2.) Some devices are masters – they generate bus clock and initiate communication on the bus, other devices are slaves and respond to the commands on the bus. In order to communicate with specific device, each slave device must have an address which is unique on the bus. 3) Physically, the I²C bus consists of the 2 active wires SDA and SCL and a ground connection. The active wires are both bi-directional. 4) Start Stop Conditions and Data Transfer - Each I2C command initiated by master device starts with a START condition and ends with a STOP condition. For both conditions SCL has to be high. A high to low transition...

This circuit allows a cheap or discarded wireless doorbell set (i.e. transmitter and receiver unit) to be used as a remote emergency stop on a high-power electrical motor or motor controller system. Circuit diagram : Wireless and Wired Emergency Stop System Circuit Diagram When the button on the wireless doorbell unit is pressed, the resulting 0 V signal from the receiver unit (‘motor E-Stop’) causes PNP  transistor T1 to be turned on. Via  transistor T2, latching relay Re1 then changes state. The same is achieved when the wired Motor E-Stop button, S1, is pressed. The reset button, S2, must be pressed to reverse the state of the latching relay. The choice of T1 and T2 is not critical they are general purpose, low voltage PNP and NPN switching  transistors  respectively,  for  which  many equivalents exist. As an EMC precaution, small capacitors (100 pF) are fitted across base resistors R1 and R2, preventing the motor  from being shut down by external  electrical noise and inter...

Are you having problems with your input Mains supply? That’s common problem associated with our input mains AC line, where a high and a low voltage conditions are quite frequently encountered by us. The simple circuit shown here can be built and installed in you house electrical board for getting a 24/7 safety from the possible dangerous AC voltage conditions. The circuit keeps the relay and the wired appliances as long as the mains input stays within a safe tolerable level and switches the load OFF the moment a dangerous or unfavorable voltage condition is sensed by the circuit. Parts List R1, R2 = 1K, P1, P2 = 10K Preset, T1, T2 = BC547B, C1 = 100uF/25V, D1 = 1N4007 RL1 = 12V, SPDT, TR1 = 0-12V, 500mA

VW CAR PASSAT ENGINE CONTROL AND AUTOMATIC SOLENOID ELECTRICAL WIRING CIRCUIT 1993 VW Passat Engine Control Module, Automatic Control Unit, and Automatic Solenoid Electrical Wiring Diagram are shown in the following figure. It shows the connection and wiring between each parts and component of Engine Control Module, Automatic Control Unit, and Automatic Solenoid system of the vehicle such as the multi-function switch, fuse/relay panel, knock sensor, coolant temperature sensor, shift lock solenoid, starter interlock/back up lit relay,automatic control computer clutch shut off relay, automatic control unit, automatic solenoids, program switch, throttle position sensor, full throttle switch, idle switch, throttle valve potentiometer, ignition booster, distributor firing order, engine control module, carbon canister, cold starter, idle air control valve, evap emission on/off valve, and many more.

The electronic circuit provides a visual time 9 second delay using ten LED before control by closing a 12 Vdc relay. That the reset switch has closed, IC 4017 decade counter will be reset to zero count which illuminates the LED driven from pin 3. IC 555 timer output at pin 3 will be high and the voltage at pins 6 and 2 of the timer will be a little less than the lower trigger point, or about 3 Vdc. 9 Sec Timer with LED Indication and Control Relay Circuit Schematic   That time the switch is opened, the transistor in parallel with the timing capacitor (22uF) is shut off allowing the capacitor to begin charging and the IC 555 timer circuit to produce an approximate one second clock signal to the decade counter. The counter advances on each positive going change at pin 14 and is enabled with pin 13 terminated low. When the 9th count is reached, pin 11 and 13 will be high, stopping the counter and energizing the relay. Longer delay times can be obtained with most capacitor or most resi...

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...

Have you ever wondered exactly what is going on in the 2.4GHz WiFi and ISM band around your house. What channel is it best to set your wireless router to? Why are you getting such poor performance across your WiFi network? Is your neighbour on the same frequency? Just what is out there? This neat little gadget will sniff the airwaves and give you a graph of the signal strength vs frequency across the entire band. It connects to your computer by USB 2.0 and with the companion Windows software you can display the spectrum or save the raw data to an Excel compatible file for some more number crunching. It uses just two significant components, a radio module from Cypress Semiconductor and a PIC microcontroller from Microchip. Total cost to build it should be less than US$30. The 2.4GHz Band The 2.4GHz ISM (Industrial Scientific Medical) band is often called the WiFi band because it is used for WiFi networking (ie, 802.11 b/g/n). This band is unlicensed, meaning that you and anyone can tran...

Tone control circuit is used to adjust the tones before entering the amplifier. Tone control over equipped with a loudness and filter directly without using the switch to disconnected or connected. Part of his filter that is C1 and R1 from ground to input , and for his loudness on the R4 and C3 are connected to the input and then go to VR1. C2 and R3 go from ground to the input . After the input is set by volume or VR1 then procesed again by treebel ie C8 , R13 , R14 , and VR2 . Bass on R10 , R11, R12 , C7 ,C8 , and VR3. For supply voltages has been given a stabilization in Q3. See schematic below : Click to view larger Part list : R1 = 100K R2 = 50K trim R3 = 22K R4 = 15K R5 = 1K R6 = 4K7 R7 = 330K R8 = 330K R9 = 3K3 R10= 5K6 R11= 8K2 R12= 5K6 R13= 1K R14= 1K R15= 50K TRIM R16= 50K TRIM R17= 330K R18= 4K7 R19= 47K R20= 1K R21= 4K7 R22= 2K2 R23= 100R R24= 22K C1 = 15n C2 = 15n C3 = 560p C4 = 4u7 C5 = 33u C6 = 4n7 C7 = 39n C8 = 39n C9 = 4u7 C10=4u7 C11=470u C12=100u Q1 = C1815 Q2 = C828...

What is electricity? Electricity is the   flow of charge   around a circuit   carrying energy   from the battery (or power supply) to components such as lamps and motors. Electricity can flow only if there is a  complete circuit  from the battery through wires to components and back to the battery again. The diagram shows a simple circuit of a battery, wires, a switch and a lamp. The switch works by breaking the circuit. With the  switch open  the circuit is broken - so electricity cannot flow and the lamp is off. With the  switch closed  the circuit is complete - allowing electricity to flow and the lamp is on. The electricity is carrying energy from the battery to the lamp. We can see, hear or feel the effects of electricity flowing such as a lamp lighting, a bell ringing, or a motor turning - but we cannot see the electricity itself, so which way is it flowing?  Imaginary positive particles moving in the direction of the conventi...

Definition of power amplifier A transistor amplifier which raises the power level of the signals that have audio frequency range is known as transistor power amplifier. In general the last stage of multistage amplifier is the power stage. A power amplifier differs from the voltage amplifier. A transistor that is suitable for power amplification is generally called as power transistor. Classification of Power Amplifier The power amplifiers can be classified in the following ways. 1.        According to the usage of Frequency Signals: (i)                   Audio frequency power amplifiers. (ii)                 Radio frequency power amplifiers. (iii)               Video frequency power amplifiers. 2.        A...

Dual-purpose test-instrument, Very simple circuitry, 1.5V Battery-operated. This simple circuit generates narrow pulses at about 700-800Hz frequency. The pulses, containing harmonics up to the MHz region, can be injected into audio or radio-frequency stages of amplifiers, receivers and the like for testing purposes. A high-pitched tone can be heard from the speaker of the device under test when all is working properly. The clip must be connected to the ground of the device under test, touching with the probe the different stages of the circuit, starting from the last stage and going up towards the first. When the tone is no longer heard, the defective stage has been found. Connecting an earclip or headphone to J1, the circuit will automatically change into a two-stage amplifier and any audio signal coming from the device under test and picked-up by the probe will be heard through the headphones. The testing of a circuit should be made in the reverse manner, i.e. starting from the first...

Ladder Logic for AND ,OR, EX OR, NAND ,NOR Gates with Truth Tables   Following table shows symbol ,truth table and Ladder diagram for AND ,OR, EX OR, NAND ,NOR Gates.

If you are in the market for a surround sound system I'm sure you are trying to learn as much as possible about options before you reach the buying stage. One thing to keep in mind is that there are many options and most of them will come down to a matter of taste when all is said and done. There is no right or wrong component or process when it comes to buying a surround sound system only what does and doesn't work for you and the space you have available. You will find throughout the process that there are many parts, pieces, and components that you may purchase for your surround sound system and even more prices for those individual items. Ultimately the decision comes down to how much of a sound snob you are. Seriously. I must admit that my personal preference is for the most possible sound saturation and the most realistic possible sound as possible. For this reason I am more interested in buying the components as individuals rather than a simple AV receiver. This does no...

The circuit consists of power supply and control sections. The power supply section is built around transformer X1, bridge rectifier BR1 and filter capacitor C1. The 50Hz, 230V AC mains is stepped down by transformer X1 to deliver a secondary output of 9V, 300 mA. The transformer output is rectified by the bridge rectifier and filtered by capacitor C1. When the mains is switched on for the first time, pin 3 of IC CD4017 (IC1) goes high and relay RL1 energises to switch on the fan. When mains is briefly switched off using S1 and then switched on, the power to IC1 is maintained by the charge on capacitor C1. At the same time, there is a trigger pulse on the clock input (pin 14) of IC1, which advances the decade counter and relay RL2 energises to switch-on the air-conditioner. Both the air-conditioner and the fan will be turned off if the switch is in the ‘off’ position. Assemble the circuit on a general-purpose PCB and enclose in a suitable case. Fix the unit onto the switchboard. Use re...

LED circuit diagram -  LED strobe has independent delay and duration The circuit applies a 5V pulse, the main clock, to diode D 1 and capacitor C 1  to form a peak-hold circuit. C 1  then discharges at a rate that P 1  sets. Michael C Page, Chelmsford, MA, USA High-brightness LEDs, with independent delay and duration, find use in a visual-inspection application. The circuit is not complex, but it saved the day in an application involving visual inspection of the spray pattern of fuel injectors for quality and consistency.