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General Description: The BA3853BFS is a dual-channel electronic volume controller built around a low-noise, low-distortion VCA. It is suited for car-audio applications, and has performance that rivals mechanical-type volume controllers. In addition to volume control, the IC includes all functions required for controlling sound quality, to allow more compact designs with far fewer components. Circuit diagram: Dual-channel electronic volume controller Datasheet for BA3853: Download

Although it does not have the same charm as real mercury barometers with long glass tubes on pieces of carved and polished wood, the Torricelli barometer discussed here is a functional equivalent and electronic replica of the Torricelli barometer. Actually, rather than displaying the atmospheric pressure on the traditional digital displays, we preferred to reproduce the general look of this respected predecessor of electronic barometers. The mercury tube is, of course, replaced by a simple LED scale which, if not as beautiful, is still less toxic for the environment in case of breakage. As indicated on the drawing, the pressure sensor utilized is a Motorola MPX2200AP. This circuit is adapted for measuring absolute pressure and has a range well suited for atmospheric pressure. Without entering too deep into the technical details, such sensors deliver an output of voltage proportional not only to the measured pressure but, unfortunately, to their supply voltage as well. Hence they must b...

This reliable and easy-to-operate electronic security system can be used in banks, factories, commercial establishments, houses, etc. The system comprises a monitoring sys-tem and several sensing zones. Each sensing zone is provided with a closed-loop switch known as sense switch. Sense switches are fixed on the doors of premises under security and connected to the monitoring system. As long as the doors are closed, sense switches are also closed. The monitoring system can be installed at a convenient central place for easy operation. Fig. 1: Monitoring circuit along with the alarm circuit Fig. 1 shows the monitoring circuit only for zone 1 along with the common alarm circuit. For other zones, the monitoring circuit is identical, with only the prefixes of components changing as per zone number. Encircled points A, B, and C of each zone monitoring circuit need to be joined to the corresponding points of the alarm circuit (upper half of Fig. 1). When zone 1 sensing switch S11, zone...

This Simple Horn Bugle Electronic Circuit Diagram just a door trigger input 4093, bound in a low frequency oscillator, as the transistor Q1, which is the IRF511 FET amplifier is directly connected to a small speaker with horn. The output frequency can be changed by adjusting potentiometer R1. Simple Horn Bugle Electronic Circuit Diagram

A bionic bird known as SmartBird has been developed by German company that can takes off, fly and land without human interference and with minimal consumption of energy. The size of the SmartBird is about 150 cm wingspan, the wings feet long, and a torso of more than one meter. Despite the dimensions, the SmartBird is very lightweight. It is powered by two small lithium batteries with half amp charge. Despite the high technology used in its mechanical structure, the key to the secret of seagull flying mechanic is within your torso. While motion sensors indicate the exact position of the wings and an accelerometer provides information about the displacement and tilt the bird, a small microprocessor system calculates the exact angle of twist of each wing and tail of the bird, which allows him to fly in different directions, take off and land without human interference. However, you can also control it via a microwave radio system known as ‘ZigBee’, which combines rapid response and low p...

This intelligent electronic lock circuit is built using transistors only. To open this electronic lock, one has to press tactile switches S1 through S4 sequentially. For deception you may annotate these switches with different numbers on the control panel/keypad. For example, if you want to use ten switches on the keypad marked ‘0’ through ‘9’, use any four arbitrary numbers out of these for switches S1 through S4, and the remaining six numbers may be annotated on the leftover six switches, which may be wired in parallel to disable switch S6 (shown in the figure). When four password digits in ‘0’ through ‘9’ are mixed with the remaining six digits connected across disable switch terminals, energisation of relay RL1 by unauthorized person is prevented.For authorized persons, a 4-digit password number is easy to remember. To energies relay RL1, one has to press switches S1 through S4 sequentially within six seconds, making sure that each of the switch is kept depressed for a duration of ...

Here is a simple Electronic Project for battery replacement power supply to build easy.  Your child's battery toy has failed and you have to fix it. Once you have managed to get it apart, the battery compartment is not likely to be connected to the works or the batteries might have gone flat anyway. The solution is this switchable supply which is designed to replace from one to six dry cells. It is not intended to replace the batteries on a permanent basis, as in most cases this is not practical. Battery Replacement Power Supply Circuit Diagram: The heart of the supply is an LM317T adjustable 3-terminal regulator and six trimpots selected by switch S1b. The other pole of the switch, S1a, is used to select taps on the transformer secondary, to minimize power dissipation in the LM317T. The table shows the trimpot settings for the six voltage outputs. Diode D1 and the 10µF capacitor and the LED provide power indication. This has the advantage of constant brightness which would not be...

This is a Electronic Alarm Circuit Project of Fire Alarm with LDR Sensor.  The fire alarm circuit which use LDR to sense the smoke from the fire, so it can be used to detect any dark smoke. With the onset of summer season, possibilities of fire accidents go up. These fire accidents could be prevented if timely alarms are available. The circuit given right here alerts the user against these fire accidents. The circuit needs to be put in fire-prone locations for example a kitchen. Fire Alarm with LDR Sensor Circuit Diagram: Every person is aware that when everything catches fire, smoke is produced. When this smoke passes between a bulb and an LDR, the amount of light falling on the LDR reduces. This causes the resistance of LDR to raise and the voltage at pin 2 of IC 555 comes below 1/3 Vcc. thus triggering IC 555 that is utilized right here in bistable mode. As a result the voltage of pin 3 goes high. This high voltage (about 9V) completes the supply to the COB (chip-on-board). Var...

An Electronic Watering Can Circuit Diagram . Summertime is holiday time but who will be looking after your delicate houseplants while you are away? Caring for plants is very often a hit or miss affair, sometimes you under-water and other times you over-water. This design seeks to remove the doubt from plant care and keep them optimally watered.  The principle of the circuit is simple: first the soil dampness is measured by passing a signal through two electrodes placed in the soil. The moisture content is inversely proportional to the measured resistance. When this measurement indicates it is too dry, the plants are given a predefined dose of water. This last part is important for the correct function of the automatic watering can because it takes a little while for the soil to absorb the water dose and for its resistance to fall. If the water were allowed to flow until the soil resistance drops then the plant would soon be flooded.  An Electronic Watering Can Circuit Diagram...

Low-Cost Electronic Project of RF Synthesizer Uses Generic ICs . You can design a hardware-based frequency synthesizer with one inexepensive IC and a few passive components. Such synthesizer chips are not always available, however, because they are typically single-sourced and are not in stock with parts distributors. The need for a working circuit in a short time and using common parts prompted the creation of the circuit in this Design Idea. The synthesizer covers the US commercial AM (amplitude-modulation) broadcast band. It tunes in 10-kHz steps from 500 to 1800 kHz, but you can scale the frequencies for other applications. The PLL (phase-locked loop) time base is a 100-kHz, tuning-fork-cut crystal of the same size as those in wrist watches. Using a more common crystal requires some extra parts to scale the frequency. Note that if you attempt to use one of these tiny crystals with a CMOS gate oscillator circuit, however, the circuit will either fail to start or exhibit visible jit...

This is a compact electronic siren circuit based on three transistors.This circuit is suitable for in corporating with other alarm or siren projects such as burglar alarms, automatic factory sirens etc or a simple push to on alarm. The  electronic siren circuit given here  is  based on a complementary transistor pair consisting of Q2 & Q3 (BC557 & BC 37)  wired as an astable multivibrator oscillator,which directly drives the speaker.The transistor Q1 is used to provide a full charge on capacitor C2 when power is turned ON. When push button switch S1 is pressed , the capacitor C2 slowly discharges through resistor R8.This makes the circuit to  oscillate at a low frequency that increases to a high frequency and kept indefinitely as the capacitor is fully discharged. When the switch P1 is released, the output  frequency decreases slowly as C2 is charged to the  positive voltage through resistance R6 and the Base-Emitter junction of tramsistor Q2. ...

This electronic combination lock can be use with an outdoor gate. The functionality is implemented in software. It turns on a relay (usually to open a door) for a few seconds if someone enters the valid code. The relay can operate a power to open type electric strike with a shorting contact or a power-to-hold type electromagnetic lock with a breaking contact (we need the relay because these locks usually work with AC, not DC). The code can be changed any time after entering the current code. Current consumption of the circuit is low, because the PIC sleeps most of the time, and wakes up only for processing key presses. The 16F628A already contains an internal RC oscillator, so no crystal is needed. Type in the correct code and use # as 'enter'. The initial code is 623342. You can change the length of code as well. * is used to change the code. Type in the actual code then press *. If you didn't miss the actual code, the code change indicator LED will light up. Then type in ...

This is a Electronic Central Image Canceller Circuit diagram Project. The circuit allows you to eliminate the vocal portion of an audio signal, while leaving the instrumental portion. The circuit mixes two channels that must be 180° out of phase, so the signals that form the center-stereo image is canceled out.    Electronic Central Image Canceller Circuit Diagram Those signals usually appear in phase. Resistor R3 biases the non inverting input of Ul from a center tap formed by resistors Rl and R4, and capacitor C3. Resistor R4, capacitor C3, and potentiometer R6 form a negative-feedback circuit that establishes the closed-loop voltage gain of Ul at unity. The signal is inverted between the input and output. Signals applied to the right input are coupled to the non inverting input of Ul through C4 and attenuating resistor R5.  Resistors R3 and R5 make up a 6 dB attenuator, so once again, there is unity voltage gain between the input and the output. However, the right inpu...

Description:  The following circuit shows about Self Switching Power Supply Electronic Circuit Diagram. This circuit based on the 7805 IC. Features: variable output voltage, every 100-ohm increment, output varies from 3.7V to 8.7V, the output voltage increases by 1 volt. Component: Transformer, Switch, Diode, Resistor, Capacitor, Transistor, IC.

This electronic cricket is a present for Kids. This simple battery powered circuit can be used to play Cricket Match with your friends. Each LED in the circuit indicates various status of the cricket match like Sixer, Run out, Catch etc. The Circuit uses two ICs ,one in the Astable mode and the second in the display driver mode. IC1 is wired as an Astable Multivibrator with the timing elements R1, R2 and C1. With the shown values of these components very fast output pulses are generated from the Astable. Output from IC1 passes into the input of IC2 which is the popular Johnson Decade counter CD4017. It has 10 outputs. Of these 8 outputs are used. Output 9 ( pin9) is tied to the reset pin 15 to repeat the cycle. When the input pin 14 of IC2 gets low to high pluses, its output turns high one by one. Resistor R3 keeps the input of IC2 low in stand by state to avoid false indications. Electronic Cricket Circuit Diagram When the Push Switch S1 is pressed momentarily, the Astable operates an...

A bionic bird known as SmartBird has been developed by German company that can takes off, fly and land without human interference and with minimal consumption of energy. The size of the SmartBird is about 150 cm wingspan, the wings feet long, and a torso of more than one meter. Despite the dimensions, the SmartBird is very lightweight. It is powered by two small lithium batteries with half amp charge. Despite the high technology used in its mechanical structure, the key to the secret of seagull flying mechanic is within your torso. While motion sensors indicate the exact position of the wings and an accelerometer provides information about the displacement and tilt the bird, a small microprocessor system calculates the exact angle of twist of each wing and tail of the bird, which allows him to fly in different directions, take off and land without human interference. However, you can also control it via a microwave radio system known as ‘ZigBee’, which combines rapid response and low p...

This Digital Electronic Lock Circuit Diagram 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. 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. Digital Electronic Lock Circuit Diagram 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 to the common point of the keypad so that the appropriate NAND gate will see two logic high levels whe...

This electronic cricket is a present for Kids. This simple battery powered circuit can be used to play Cricket Match with your friends. Each LED in the circuit indicates various status of the cricket match like Sixer, Run out, Catch etc. The Circuit uses two ICs ,one in the Astable mode and the second in the display driver mode. IC1 is wired as an Astable Multivibrator with the timing elements R1, R2 and C1. With the shown values of these components very fast output pulses are generated from the Astable. Output from IC1 passes into the input of IC2 which is the popular Johnson Decade counter CD4017. It has 10 outputs. Of these 8 outputs are used. Output 9 ( pin9) is tied to the reset pin 15 to repeat the cycle. When the input pin 14 of IC2 gets low to high pluses, its output turns high one by one. Resistor R3 keeps the input of IC2 low in stand by state to avoid false indications. Electronic Cricket Circuit Diagram When the Push Switch S1 is pressed momentarily, the Astable operates an...

It is a simple and low-cost Electronic Circuit Project of Picture Fixer Inverter Circuit. The circuit will accept a video signal, separate the sync pulses, invert the video, and add new video to the old sync pulses. The video signal is brought in through Jl and applied to a clamping circuit consisting of Cl, Dl, D2,D3, Rl, and R2. The clamp circuit forces all of the sync pulses to align with the same de voltage level. With the video voltage clamped, the trip points of the comparators that follow can be set with trimmer resistors R3 and Rll. Picture Fixer Inverter Circuit Diagram: The resistors will not have to be readjusted. One comparator, Ul, is adjusted to change states with a change in either video or sync-pulse levels. The other comparator, U2, is adjusted to trip on changes of sync-pulse levels only. The output of Ul now consists of a logic level, 0 to +5 V, signal that contains both sync pulses and video. The composite signal is coupled to an EXCLUSIVE-OR gate, U3a, where it is...

Here’s a simple programmable electronic dice with numeric display . This dice can be programmed using a 4-way DIP switch to display any random number between ‘1’ and ‘2,’ ‘1’ and ‘3,’ ….. or ‘1’ and ‘9.’ To obtain the desired dice range, inner switches A, B, C and D of DIP switch are to be set as per the table. For example, if you want the electronic dice to count from 1 to 8, close switches A and D and keep B and C open. On pressing switch S1, the display varies fast between ‘1’ and ‘8.’ When you release S1, the display stops shuffling and the last (latest) number remains on it. IC1 is a dual 4-input Schmitt trigger NAND gate 74LS13. Gate N1 is used as an oscillator built using resistor R2 and capacitor C1 to produce approximately 70kHz clock frequency, which is fed to IC2. Gate N2 loads data at the inputs of IC2. IC2 is a presettable binary counter (74LS191) with parallel loading facility. Whenever its pin 11 goes low, the data present at its inputs D through A (which is ‘0001’) appe...