My Circuit

A very simple heat detector alarm electronic project can be designed using the UM3561 sound generator circuit and some other common electronic parts . This heat detector electronic circuit project uses a complementary pair comprising npn and pnp transistor to detect heat Collector of T1 transistor is connected to the base of the T2 transistor , while the collector of T2 transistor is connected to RL1 relay T3 and T4 transistors connected in darlington configuration are used to amplify the audio signal from the UM3561 ic. When the temperature close to the T1 transistor is hot , the resistance to the emitter –collector goes low and it starts conducting . In same time T2 transistor conducts , because its base is connected to the collector of T1 transistor and the RL1 relay energized and switches on the siren which produce a fire engine alarm sound. This electronic circuit project must be powered from a 6 volts DC power supply , but the UM3561 IC is powered using a 3 volt zener diode , bec...

Build a 12V To 24V DC-DC Converter Circuit Diagram .This simple 12V To 24V DC-DC Converter Circuit Diagram can provide up to 24V from a 12V source. It can be used to run radios, small lights, relays, horns and other 24V accessories from a 12V vehicle with a maximum draw of about 800mA.  It can be used to charge one 12V battery from another, or step up the voltage just enough to provide necessary overhead for a 12V linear regulator. Using one op-amp as a square wave oscillator to ring an inductor and another op-amp in a feedback loop, it won't drift around under varying loads, providing a stable 24V source for many applications. With a wide adjustment in output this circuit has many uses.  12V To 24V DC-DC Converter Circuit Diagram Parts Part Total Qty. Description Substitutions R1, R2, R3, R4, R8, R7 6 100K 1/4W Resistor R5 1 470 Ohm 1/2W Resistor R6 1 10K Linear Pot C1 1 0.01uF Mylar Capacitor C2 1 0.1uF Ceramic Disc Capacitor C3 1 470uF 63V Electrolytic Capacitor D1 1 ...

This is stereo audio amplifier with based on ICTDA2824S , Minimum voltage require 3 volts and maximum voltage 17 volts . Maximum output power 2 X 2 Watt , its low power amplifier. Output impedance  4 ohm. see schematic audio below :

Here is a compact low cost FM radio circuit using IC TDA 7000. This circuit is designed as per the data sheet and the result is excellent.Ideal for all category of electronic enthusiasts. Single Chip FM Radio Circuit Diagram The TDA7000 is a monolithic integrated circuit for mono FM portable radios, where a minimum on peripheral components is crucial. The IC TDA 7000 has a Frequency-Locked-Loop system with an intermediate frequency of 70 kHz. The intermediate frequency selectivity is achieved by active RC filters. The only function which needs alignment is the resonant circuit for the oscillator, thus selecting the reception frequency. Spurious reception is avoided by means of a mute circuit, which also eliminates too noisy input signals. Special steps are taken to meet the radiation requirements.  Notes:   For L1 and L2 wind 5 turns of 0.6 mm enameled Copper wire on a 4 mm dia plastic former. For antenna use a 50mm long insulated copper wire. IC TDA 7000 can withstand up...

The 100Khz Multiple Output Switching Power Supply Circuit Diagram uses two VN4000A 400-V MOS POWER FETs in a half-bridge power switch configuration. Outputs available are + 5 Vat 20 A and ±15 V (or ±12 V) at 1 A. Since linear three-terminal regulators are used for the low-current outputs, either ±12 V or ±15 V can be made available with a simple change in the transformer secondary windings. A TU94 switching regulator IC pro Vides pulse-width modulation control and drive signals for the power supply. The upper MOS POWER FET, Q7. in the power switch stage is driven by a simple transformer drive circuit. The lower MOS. Q6, since it is ground referenced. is directly driven from the control !C. 100Khz Multiple Output Switching Power Supply Circuit Diagram

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There is a wide variety of NiCd (nickel-cadmium) battery chargers on the market, but there are not many that can work from an in car 12 V cigar lighter. Such a charger would, for instance, be of interest to campers and caravanners who do not have a 230 V a.c. mains supply available. To satisfy the needs of these users, a charger could be designed for operation from the cigar lighter, but it is, of course, of far greater interest if it could also work from the domestic mains supply. Furthermore, it would also be very useful if a number of cells, say, 1 to 4, of different format could be charged simultaneously. Lastly, another benefit would be if the charger would automatically switch off once the battery or cells have been charged fully. The charger described in this article does all that: it accommodates batteries or cells Type R6 and R14. Switching off after a period of 2 h 30 m, 5 h, or 10 h is arranged by 3-way switch S1. The 2 h 30 m period is for charging Type R6 batteries (1/2 ch...

This is a Simple Single Supply Voltage Regulator Circuit Diagram. The circuit uses a CA3140 BiMOS op amp capable of supplying a regulated output that can be adjusted from essentially 0 to 24 volts. The circuit is fully regulated. Simple Single Supply Voltage Regulator Circuit Diagram

This chassis does not contain a specific Service mode. The Services and device setting can be made via Mode the Technical Assistance Factory. There is no program on TV Check method: Check the closed circuit to the tuner IC image encoder for detecting whether components defective. Or check if the resistance R117, R118, R203 and R204 has increased may cause the problem. No Good Picture or Dual Image Check the signal IF1 / IF2 to Q101 and relevant circuit. In this case the problem can be Q101 and / or SAW 101. No Picture or Color Correct • Check the circuit IC201 to RGB. • Check the welding IC and physical damage of the relevant circuit or check defective capacitors. Image with White Line Horizontal and Audio Check voltage supply of vertical IC301 and circuit relevant, and check the vertical sync signal IC201. Control Evil Operation Remote Check voltage at pin 64 of IC201. The normal value should be 5.15V. If correct check the welding connections front control panel. If it cannot be resol...

This circuit based on IC TDA3000 or you can use IC TDA2870 , minimum voltage require 12 volts and maximum voltage require 35 volts DC. Maximum ouput power 30 Watts mono audio amplifier with 4 Ohm impedance. see below the circuit :

In an audio amplifier the quality of sound depends upon a number of factors, e.g. quality of active and passive components, circuit configuration, and layout. To an extent, the selection of components depends on the constructor’s budget. The discrete active components like transistors have been increasingly replaced by linear ICs, making the task of designer easier. With the passage of time, the general-purpose op-amps like LM741, which were being used in audio/hi-fi circuits, have become The preamplifier circuit presented here is based on a dual precision op-amp for the construction of a low distortion, high quality audio preamplifier. Circuit diagram : A Low Distortion Audio Pre-amplifier Circuit Diagram   A dual op-amp OPA2604 from Burr-Brown is used for all the stages. The FET input stage op-amp was chosen in this context it is worthwile to mention another popular bi-polar architecture op-amp, the NE5534A. It has, no doubt, an exceptionally low noise figure of 4nV/ÖHz but res...

Here is a 100 Watt inverter circuit using minimum number of components. I think it is quite difficult to make a decent one like this with further less components.Here we use CD 4047 IC from Texas Instruments for generating the 100 Hz pulses and four 2N3055 transistors for driving the load. The IC1 Cd4047 wired as an astable multivibrator produces two 180 degree out of phase 100 Hz pulse trains. These pulse trains are preamplified by the two TIP122 transistors.The out puts of the TIP 122 transistors are amplified by four 2N3055 transistors (two transistors for each half cycle) to drive the inverter transformer.The 220V AC will be available at the secondary of the transformer . Nothing complex just the elementary inverter principle and the circuit works great for small loads like a few bulbs or fans.If you need just a low cost inverter in the region of 100 W, then this is the best. Circuit diagram: Parts: P1 = 250K R1 = 4.7K R2 = 4.7K R3 = 0.1R-5W R4 = 0.1R-5W R5 = 0.1R-5W R6 = 0.1R-...

This project flashes eight LEDs in an apparently random manner. It uses a 4060 combined counter and display driver IC which is designed for driving 7-segment LED displays. 8 Random Flashing LEDs Circuit Diagram The sequence is not really random because seven of the LEDs would normally be the display segments, the eighth LED is driven by an output that is normally used for driving further counters. The table below shows the sequence for the LEDs. You can use less than eight LEDs if you wish and the table may help you decide which ones to use for your purpose.

A photo or slightly activated relay normally open relay in the closed circuit / contact with the light. In this circuit, a photodiode is used to sense light. The photodiode has a high resistance in the absence of light strikes. The photodiode is connected to the reverse biased state. The only current flowing through it will be due to minority carriers. Photo Sensor Control Relay  Circuit Diagram When light falls on it, the minority current carriers in the wake of increasing the diode provides a low resistance. Because the voltage across the diode will not be sufficient to bias transistor Q1 and will be reset. Where there is darkness, the resistance increases photodiode and the voltage across it will be enough to move forward bias the transistor Q1 of the relay ON. The diode D2 is used as a diode to protect transistor switching transients produced relay. In this way, the load on the relay contacts can be switched on and off using light strikes the photodiode.

Women might say that they will never be able to have enough handbags and shoes (generally speaking), while men might never get enough of their power tools and hardware toys, and kids with their video games, but I am quite sure that something most of us will be able to agree on would be this – you can never have enough power outlets around, considering the rather large number of gadgets that we carry around with us these days. Smartphones, tablets, digital cameras, smart watches, the list goes on and on, and Thinkgeek intends to help you out with the $34.99 Smart AC Automotive Power Strip. The Smart AC Automotive Power Strip will be able to juice up just about all things, where this inverter plugs into your cigarette lighter socket. It will come with a couple of USB power ports and two AC outlets, and fret not about it melting down or catching fire, since the safety features which have been thrown into the mix include over-voltage, overload, short-circuit, high-temperature protection, a...

4.2.4 Mercury Cell This cell is also m common use and consists of: an outer steel Container as the positive electrode, a cylinder of compressed zinc powder in the centre of the cell as the negative electrode potassium hydroxide as the electrolyte surrounding the zinc plate, and manganese dioxide and carbon as the depolarizing mixture. The cell is constructed so small that it is commonly used in watches, hearing aids, and miniature calculators. Its voltage is 1.35 V. Mercury cell The most important features of the mercury cell are: It can be stored for long periods without losing its charge through local action. It has a very high energy output for its size Its drawbacks are: It is toxic due to high mercury content It is expensive This cell has been replaced with a safer silver oxide cell.

This light activated relay circuit presented here uses the 555 timer IC and a light dependent resistor or LDR to form a light sensitive relay in an intruder alarm system or for switching on a lamp at Sun set and off at Sun rise. Potentiometer R1 value must be chosen and then adjusted that under normal conditions when the light is falling on the LDR the voltage across the LDR is less than 1/3 of Vcc. The output of the 555 IC is high now. The actual value of R1 will depend on the resistance of the LDR. When the light fades or is interrupted by an intruder, the voltage across it rises above 2/3 of Vcc, tripping the IC flip-flop. The output goes low activating the relay. When the light is restored, voltage falls below 1/3 of Vcc, again tripping the flip-flop causing the output to go high and the relay drops. The difference of 1/3 of Vcc between turning on and turning off voltages prevents relay chatter. This differential can be reduced by connecting a resistor R2 shown dotted in the schema...

This circuit controls resistive and inductive loads up to 2,500W. It's main functional device is an integrated phase control circuit - Siemens TLE3103. It contains its own power supply, a zero voltage crossing detector circuit and a logic driver. An additional feature is the low voltage input to enable/disable triac firing enabling/disabling the logic driver. The function is as follows: pin13 TLE3103 open (floating), trigger output active, tied to ground trigger output disabled. 2500W Phase Control  Circuit diagram An UP and a DOWN button control a 32-step digital potentiometer (IC2, AD5228) via the debouncer IC1 (MAX6817). The potentiometer has a power on reset pin which might be tied to ground causing the potentiometer to start at midscale, or to VCC causing it to start at zero scale. The desired function is selectable using jumper JP1. The triac (capable of driving 40A loads) is a bit overkill for the desired power but the BTA41 has an isolated body and therefore handling of the...

Many electronic projects require the use of a small audio amplifier. Be it a radio transceiver, a digital voice recorder, or an intercom, they all call for an audio amp that is small, cheap, and has enough power to provide adequate loudness to fill a room, without pretending to serve a disco! About one Watt RMS seems to be a convenient size, and this is also about the highest power that a simple amplifier fed from 12V can put into an 8 Ohm speaker. A very low saturation amplifier may go as high up as 2 Watt, but any higher power requires the use of a higher voltage power supply, lower speaker impedance, a bridge circuit, or a combination of those. During my many years building electronic things I have needed small audio amps many times, and have pretty much standardized on a few IC solutions, first and and foremost the LM386, which is small, cheap, and very easy to use. But it does not produce high quality audio... For many applications, the advantages weigh more than the distortion an...

As versatile as electromechanical relays can be, they do suffer many limitations. They can be expensive to build, have a limited contact cycle life, take up a lot of room, and switch slowly, compared to modern semiconductor devices. These limitations are especially true for large power contactor relays. To address these limitations, many relay manufacturers offer “solid-state” relays, which use an SCR, TRIAC, or transistor output instead of mechanical contacts to switch the controlled power. The output device (SCR, TRIAC, or transistor) is optically-coupled to an LED light source inside the relay. The relay is turned on by energizing this LED, usually with low-voltage DC power. This optical isolation between input to output rivals the best that electromechanical relays can offer. Being solid-state devices, there are no moving parts to wear out, and they are able to switch on and off much faster than any mechanical relay armature can move. There is no sparking between contacts, and n...

It is a simple circuit of optical index of level of sound signals, adapted in various needs of user. It can be adapted in various levels of entry, regulated from trimmer TR1 (Level) - TR2 (Gain), then it is rectified by the D1-2 (cutting off of negative periods of signal-rectification) and drived to the main circuit of index, that it is constituted by D3...D13 , the transistors Q2-Q13 and the materials that exist around them. Circuit Diagram:  The optical index him we take from the line of LED LD1-13. The each led turns on when the level is altered at 0,65V roughly. The requirements in current are 100 ma with complete index. We can add all units LED we want, always calculating the current where they will need the news LED. Parts List:

Circuit of an automatic switch for audio power amplifier stage is presented here. The circuit uses stereo preamplifier output to detect the presence of audio to switch the audio power amplifier on only when audio is present. The circuit thus helps curtail power wastage. IC1 is used as an inverting adder. The input signals from left and right channels are combined to form a common signal for IC2, which is used as an open loop comparator. IC3 (NE556) is a dual timer. Its second section, i.e., IC3(b), is configured as monostable multivibrator. Output of IC3(b) is used to switch the power amplifier on or off through a Darlington pair formed by transistors T1 and T2. IC3(a) is used to trigger the monostable multivibrator whenever an input signal is sensed. Circuit diagram: Automatic Switch For Audio Power Amplifier Circuit Diagram Under ‘no signal’ condition, pin 3 of IC2 is negative with respect to its pin 2. Hence the output of IC2 is low and as a result output of IC3(a) is high. Since t...

LM2758 FLASH LED DRIVER EVALUATION BOARD ELECTRONIC DIAGRAM To startup the Evaluation board, set the EN1 jumper and EN2 jumper to the “OFF” position, apply power to the board, and then move the EN jumper(s) to the “ON” position. This is the expected startup operation in the typical application where VIN is tied to a voltage rail and the EN pins are controlled via logic signal.

This is the simple IC TL081 based 4 microphones mixer Circuit Diagram. A TL081 op amp is used as a high impedance to low. converter and a signal mixer. The input impedance is about 1 megohm and the output impedance is about 1 kohm. Two 9 volt batteries are used as power source. Battery must be several hundreds of hours with alkaline batteries. IC TL081 based 4 microphones mixer Circuit Diagram

This is the Simple Resistance ratio Detector Circuit Diagram.  Photoelectric control, temperature detection and moisture sensing require a circuit that can accurately detect a given resistance ratio. A simple technique that uses an op amp as a sensing element can provide 0,5% accuracy with low parts cost. The reed-relay contacts close when the resistance of the sensor Rp equals 47% of the standard Rs.  Simple Resistance ratio Detector Circuit Diagram Adjusting either Rl or R2 provides a variable threshold; the threshold is controlled by varying R3. For the most part, the type of resistors used for Rl and R2 determines the accuracy and stability of the circuit. With metal-film resistors, less than 0.5% change in ratio sensing occurs over the commercial temperature range (0 to 70 C) with ac input variations from 105 to 135 V.

This Park-Aid Circuit Diagram was designed as an aid in parking the car near the garage wall when backing up. LED D7 illuminates when bumper-wall distance is about 20 cm., D7+D6 illuminate at about 10 cm. and D7+D6+D5 at about 6 cm. In this manner you are alerted when approaching too close to the wall. All distances mentioned before can vary, depending on infra-red transmitting and receiving LEDs used and are mostly affected by the color of the reflecting surface. Black surfaces lower greatly the device sensitivity. Obviously, you can use this circuit in other applications like liquids level detection, proximity devices etc. Circuit operation: IC1 forms an oscillator driving the infra-red LED by means of 0.8mSec. pulses at 120Hz frequency and about 300mA peak current. D1 & D2 are placed facing the car on the same line, a couple of centimeters apart, on a short breadboard strip fastened to the wall. D2 picks-up the infra-red beam generated by D1 and reflected by the surface placed...

A 4-cell pack is a convenient, popular battery size. Alkaline manganese batteries are sold in retail stores in packs of four, which usually provide sufficient energy to keep battery replacement frequency at a reasonable level. Generating 5 V from four batteries is, however, a bit tricky. A fresh set of four batteries has a terminal voltage of 6.4 V, but at the end of their life, this voltage is down to 3.2 V. Therefore, the voltage needs to be stepped up or down, depending on the state of the batteries. A flyback topology with a costly, custom designed transformer could be used, but the circuit in the diagram gets around the problem by using a flying capacitor together with a second inductor. Circuit diagram:   The circuit also isolates the input from the output, allowing the output to go to 0 V during shutdown. The circuit can be divided conceptually into boost and buck sections. Inductor L1 and switch IC1 comprise the boost or step-up section, and inductor L2, diode D1 and capac...

The HA13158A is four-channel BTL amplifier IC designed for car audio, featuring high output and low  distortion, and applicable to digital audio equipment. It provides 34 W output per channel, with a 13.7 V  power supply and at Max distortion. Circuit diagram: 34 W × 4-Channel BTL Power IC Datasheet for HA13158A: Download

The test beeper generates a sinusoidal signal with a frequency of 1,000 Hz, a common test  frequency for audio amplifiers.  It consists of a classical Wien- Bridge oscillator (also known as  a Wien-Robinson oscillator). The network that determines the  frequency consists here of a series connection of a resistor and  capacitor (R1/C1) and a parallel connection (R2/C2), where  the values of the resistors and  capacitors  are  equal  to  each  other. This network behaves, at  the oscillator frequency (1 kHz  in this case), as two pure resistors. The opamp (IC1) ensures  that the attenuation of the net- work  (3  times)  is  compensated  for.  In  principle  a  gain  of  3 times should have been sufficient to sustain the oscillation,  but  that  is  in  theory.  Because  of tolerances in the values, the  amplification needs to be (automatically) adjusted.   Circuit diagram: Test Beeper For Your Stereo circuit Diagram   Instead of an intelligent amplitude  controller  we  chose  for...

In many projects use is made of alphanumeric LCDs that are driven internally by Hitachi’s industry-standard HD44780 controller. These displays can be driven either in 4-bit or 8-bit mode. In the first case only the high nibble (D4 to D7) of the display’s data bus is used. The four unused connections still deserve some closer attention. The data lines can be used as either inputs or outputs for the display. It is well known that an unloaded output is fine, but that a floating high-impedance input can cause problems. So what should you do with the four unused data lines when the display is used in 4-bit mode? This question arose when a circuit was submitted to us where D0-D3 where tied directly to GND (the same applies if it was to +5 V) to stop the problem of floating inputs. The LCD module was driven directly by a microcontroller, which was on a development board for testing various programs and I/O functions. There was a switch present for turning off the enable of the display when it wa...

The bi-directional sequencer uses a 4 bit binary up/down counter (CD4516) and two "1 of 8 line decoders" (74HC138 or 74HCT138) to generate the popular "Night Rider" display. A Schmitt Trigger oscillator provides the clock signal for the counter and the rate can be adjusted with the 500K pot. Two additional Schmitt Trigger inverters are used as a SET/RESET latch to control the counting direction (up or down). Be sure to use the 74HC14 and not the 74HCT14, the 74HCT14 may not work due to the low TTL input trigger level. When the highest count is reached (1111) the low output at pin 7 sets the latch so that the UP/DOWN input to the counter goes low and causes the counter to begin decrementing.  When the lowest count is reached (0000) the latch is reset (high) so that the counter will begin incrementing on the next rising clock edge. The three lowest counter bits (Q0, Q1, Q2) are connected to both decoders in parallel and the highest bit Q3 is used to select the appropr...

hile many power supplies can be set to limit their output current to a defined level, to protect the circuit they are powering, no such protection is available if you are powering a circuit from a battery. If a fault develops, the circuit can blow before you have a chance to disconnect it. Of course, you can fit a fuse in series with the supply line to the circuit under test but it will blow if a fault develops. Or perhaps it won’t blow sufficiently quickly to protect the circuit. And repeatedly having to replace fuses becomes a nuisance as well. The alternative is to use an electronic fuse. This circuit uses a relay to make and break the circuit. The current drain of the circuit under test is monitored by a 1O 2W resistor which is placed in series with the supply line. The voltage across this 1O resistor is monitored by op amp IC1a which has an adjustable gain of between 11 and 16, as set by trimpot VR1. The resultant DC voltage from pin 1 of IC1a is fed to pin 5 of IC1b which is conf...

This circuit is more of a DC to AC inverter, it uses a 555 IC as a low frequency oscillator, adjustable, adjustment can be done by the potentiometer R4 and frequency should be between 50-60 Hertz. The pulses from the IC 555 will go to Q1 and Q2 are amplified and sent to the transformer T1, which has its winding reversed. Capacitor C4 and coil L1 filter are the input to T1, it effectively ensures that a sine wave is formed.  DC to AC Inverter with 555 Circuit Diagram List of components R1 = 10K R2 = 100K R3 = 100 ohms R4 = 50K potmeter C1, C2 = 0.1μF C3 = 0.01μF C4 = 2700μF Q1 = TIP41A, NTE196, ECG196 Q2 = TIP42A, NTE197, ECG197 L1 = 1μH T1 = Transformer

Build a 10 LED Bar Dot VU meter circuit based LM3915. It differs in many respects from other applications on the same chip. The circuit is intended for those who want a VU meter that is connected directly to the output of an power amplifier.  10 LED Bar Dot VU Meter Circuit based LM3915 Circuit Diagram It’s possible to adjust the sensitivity to work with amplifiers that have different output power, you just need to change the value of R1 according to Table 1. In case you did’n find the exact resistor value, then choose the next standard value (for example if you cannot find 33K ohm, then find the 36K ohm), or if you want maximum accuracy you need to put resistors in series or in parallel to achieve the correct value.   You can use various types of LEDs (round or square) to get the visual and aesthetic result you want. The switch S1 will allow you to choose whether VU meter will work as a bar or one by one (dot). In position ON [closed switch], the LED operation is Bar, while i...