I need to make a small 4-10 second (changeable) delay circuit that pulses a cell phone vibrational motor every 0.75 seconds. I`m using a 9 volt battery. Could anyone....

This Circuit is a DPM or digital panel meter. It has a analog bar graph display and a 3-1/2 digit digital display. ICL7107 is used in the 200mV configuration. U4A opamp LF353 amplifies the 200mV Full scale input to the level required for the LM3914 display....

However effective a domestic alarm system may be, it`s invariably better if it never goes off, and the best way to ensure this is to make potential burglars think the premises are occupied. Indeed, unless you own old masters or objects of great value likely....

The aim of the project is to build simple low cost inductance meter. The main parts of the project are IC 555, Transistor, resistor and capacitor....

This digital frequency meter of circuit is succinct, software potentiality is fully excavated, the survey accuracy of the low frequency band is high, have prevented the invasion of the interference effectively. The distinctive quality has embodied in and....

After much reading and discussion, I think I`ve settled on the plans for an upcoming build for a single-ended 300B integrated amplifier. The circuit....

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Tro telephones can be used as an intercom by using this circuit. Older style rotary phones that are nonelectronic might work best in this application. Also, handsets only might be powered this way....

This project uses an LM3915 bar-graph IC driving two sets of ten LEDs for a 30dB range. The circuit is unique because it has an additional range of 20dB provided by an automatic gain control to allow it to be very sensitive to low sound levels but it....

This versatile circuit provides a selection of different switching modes. It can be used as two entirely separate toggle switches - with each push button successively energizing and de-energizing its own relay. Or the two switches can be interlinked with....

These two circuits are multi-range timers offering periods of up to 24 hours and beyond. They can be used as repeating timers - or as single-shot timers. Both circuits are essentially the same. The main difference between them is their behaviour in....

A digital AF (audio frequency) counter can be constructed with only few components by using a single 7226B IC from Intensil as shown in the diagram. The upper frequency limit of this circuit is 9 MHz. The four important functions in the frequency counter....

The schematic circuit design is for a 250 watt output, while the pics are of my 1500 watts inverter that i built, to increase the power of the circuit you have to add more of the Q7 and Q8 transistors in parallel, each pair you add will increase your power....

This circuit is designed to digitally increase/decrease the volume of an analog audio signal. It uses a single AVR microcontroller to produce the controlling pulse width modulated (PWM) signal. However, the circuit`s innovation is the use of the....

If you are lucky enough to have a big house, a large garden, and small children, this project just might interest you. It`s actually a telephone ringer capable of making any mains-powered device work from the ringer of your fixed line. With it, you will be....

Car Inverter (Power Converter, Power Inverter) is a way to convert the DC DC12V and AC220V AC mains the same for general electrical use, is a convenient vehicle power adapter. Car power inverter has been generally welcomed in foreign markets. In foreign....

A very simple and efficiency active antenna electronic project can be designed using this electronic schematic circuit that is based on transistors. This active antenna electronic project is useful for a wide range of RF frequencies covering three RF bands....

ULTRA PURE 125KHz SINE WAVE SIGNAL SOURCE . For some RFID systems, which is at 125KHz, a very low distortion signal source is required. The circuit on this page results in a 10-volt peak-peak signal into...

The LMH6703 is a very wideband, DC coupled monolithic operational amplifier designed specifically for ultra high resolution video systems as well ....

300W Subwoofer Power Amplifier. High power amps are not too common as projects, since they are by their nature normally difficult to build, and are expensive.  A small error during assembly...

Here the complete electrical circuit diagram of line follower robot which built based on ATmega16. There are three modules of line follower robot circuit that are sensor module, microcontroller module and DC motor module. ..

This circuit is a resonant twin-t filter. In this circuit, its purpose (according to the creator), is to give a decent fake lowpass response , which it does fairly well. Tim`s schematic shows two variations, one with self-oscillation, and one without. I....

This simple circuit will produce an alarm whenever the temperature falls below zero degree. A thermistor is used here to sense temperature. The op-amp LM7215 is used to compare the reference voltage and voltage from the thermistor network. Reference voltage....

This circuit is a 555 timer IC connected as a square-wave generator. Its base frequency is approximately 45 kHz, as determined by the values of R1, R2, and C1. The 45-kHz carrier is frequency modulated by a modified trapizoidal voltage waveform applied to....

A high impedance DC voltmeter using a uA741 IC is shown here. The operational amplifier is used as a non-inverting DC amplifier in which the negative feedback is through a DC meter requiring 1mA for full scale deflection. Since R6 is 100 Ohms, the meter will....

Today, almost all computers contain logic blocks for implementing a USB port. A USB port, in practice, is capable of delivering more than 100 mA of continuous current at 5V to the peripherals that are connected to the bus. So a USB port can be used, without....

The ultimate source of energy is Sun. it is possible to generate current from sunlight using solar panels. These panels convert light energy into electrical energy. A solar panel consisting of a number of solar cells, which will produce a small amount of....

It consists in 555 feet, respectively, of 1, 2-cited two-pin, using two needles with a high water level higher than 555 when the probe capacitance between 1, 2 feet circuit leaving 555 low potential output. Contrary to the output of high potential (555....

In this circuit the 555 Timer IC is connected as a astable multivibator and a 12 volt relay is derived through the pin 3 of the IC. The IC generates continues pulses at pin 3 which will activate and deactivate or flash the relay accordingly. The flashing....

This circuit uses a 1458 dual op-amp to form a radar detector. C1 is the detector of the radar signal. The first op-amp forms a current-to-voltage converter and the second op-amp buffers the output to drive the piezo transducer. R5 sets the switching....

The LM380 is a power audio amplifier for consumer applications. In order to hold system cost to a minimum, gain is internally fixed at 34 dB. A unique input stage allows ground referenced input signals. The output automatically self-centers to one-half the....

This circuit is derived from an application note of L296, It is a Power Switching Regulator from ST. The advantage of using a switching regulator is that there is not much Heat Dissipation in this circuit. If you had to build the same with a series....