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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...

The Voltage Regulator Circuit Using LM317 circuit diagram shows a way of powering a two-way mobile radio using the LM317T voltage regulator. The LM317 T is an adjustable 3-terminal positive voltage regulator that efficiently provides a load current of 1.5 Amps over an output range of 1.2 V and 37 V. With reference to the circuit, it can accept 14 volts without any hassle and the voltage can be controlled easily with the use of a potentiometer, a 3-terminal resister with sliding contact. The whole circuit will contain the following components: Printed Circuit Board (PCB) Resistor 1 (R1): 270 ohms Resistor 2 (R2): 2K carbon potentiometer Capacitor 1 (C1): 100nF Capacitor 2 (C2): 1uF tantalum LM317T Voltage Regulator Heat Sink DC Power Jacks Green LED: Power Red LED: Over Voltage Zener Diode: over voltage LED switch The zener diode switches on the over voltage LED if the voltage passing through is larger than the breakdown or preset voltage. The use of zener diode permits a constant amou...

Tiny Audio Amplifier Using LM386 Specifications The Tiny Audio Amplifier kit is a good choice for battery operation. It is based on LM386 IC. Power supply - 6 - 12 VDC Output power - 1 W, 8 Ohm The quiescent power drain is only 24 mW when operating from 6 VDC Self-centering output quiescent voltage Onboard PRESET to adjust volume Terminal pins for connecting power supply, audio signal and speaker Power-On LED indicator ON/OFF PCB mounted slide switch for power supply Four mounting holes of 3.2 mm each PCB dimensions 44 mm x 44 mm Schematic Inputs - Outputs configuration    Parts List  PCB

The Maxim MAX 6665 (www.maxim-ic.com) provides a complete temperature-dependent fan controller. It can switch fans operating at voltages of up to 24 V and currents of up to 250 mA. The IC is available from the manufacturer in versions with preset threshold temperatures between +40 °C (MAX6665 ASA40) and +70 °C (MAX6665 ASA 70). The device’s hysteresis can be set by the user via the HYST input, which can be connected to +3.3 V, connected to ground, or left open. The following table shows the hysteresis values available: HYST = Hysteresis open = 1 °C ground = 4 °C +3.3V = 8 °C Circuit diagram: Fan Controller Circuit Diagram The other pins of the SO8 package are the FORCEON input and the status outputs WARN, OT and FANON. The test input FORCEON allows the fan to be run even below the threshold temperature. The open-drain output WARN goes low when the temperature rises more than 15 °C above the threshold temperature, while the open-drain output OT indicates when the temperature is mo...

This is the Project of  Simple IC TDA2030 Complete tone Control Circuit Diagram. This circuit that use IC TDA2030, but this series is equipped with a tone control. Tone controls include Bass, Treble, and Volume. Power amplifier and tone control has been put together in a single PCB. This amplifier is a mono amplifier type, can be modify for guitar amplifiers .  If not coupled amplifier (mic preamp) then you must deactivated potensio treble and bass, why? because if not using a mic preamp and still maintain potensio treble and bass sound input (input) from the guitar will not or the maximum discharge is not tight on the speakers . So you must deactivated a way to decide which directly connected capacitor  with the tone control circuit, and capacitor were connected directly to potensio volume and input jack.   TDA2030 Complete Tone Control Circuit Diagram PCB Layout   TDA2030 Complete Tone Control Circuit Diagram PCB

This is a circuit for emergency lighting with LEDs that uses electricity from the telephone line . Generally the phone line has a DC voltage 48V and somewhere around 20 mA , and when the phone rings , the voltage rises to 96V AC . This works in a way that the phone line will not be busy while the LEDs are turned on and when you pick up the phone , the light goes off and lets you use your phone normally .  Emergency Light using Phone Line Circuit Diagram

The TV remote control transmits television signals as pulses of frequency around 37.5kHz. Each button on the remote control is pressed or equivalent has a pulse signal codes. This remote transmits pulses of the circuit block of the same frequency as the remote to your TV confuse decoding the transmitted signal. The heart of the circuit is the 555 timer IC in astable circuit works mode.The output series of pulses at a frequency of 18 kHz to 48 kHz by simply adjusting the 5K potentiometer. What you do is adjust the potentiometer until frequeny jives to its distance from the TV or until the signal is ignored by television. TV Remote Jammer Using 555 IC Circuit Diagram

This timer circuit is designed to switch on a 12 V load in a solar-powered installation for a preset period at the press of a button. When the period has expired a latching relay disconnects both the load and the controller circuit from the 12 V supply. The length of the period can be configured by making suitable changes to the microcontroller’s source code. When button S1 is pressed a voltage appears across relay coil L1, and the relay switches the load on. Since the relay is a latching type, it remains in this state when the but ton is released. There is now a supply to the 78L05 voltage regulator (a low-dropout type such as the LP2950CZ-5.0 may also be used) and the microcontroller is powered up. In the microcontroller the timer program runs until the configured time interval has elapsed. Around 90 % of the way through the time period LED D2 lights as a warning that the load will shortly be switched off, and this time can also of course be configured by changing the software. When ...

This hack illustrates how a car can be controlled from anywhere in the world by tapping into the disgnostic systems and onboard webserver of the car. The objective is to keep the car “live” and connected to the Internet 24×7 even when not being driven. It should run continuously without flattening the car battery by critically selecting a low-power computer. Also, the user should be able to start the engine, pop the trunk, lock/unlock, and view all vehicle diagnostics from his iPhone. The chosen car was a Mazda RX-8 as shown in the image below. It was released in 2004 and consists of 6-speed manual transmission with a 1.3L 13B-MSP RENESIS engine. The computer used in this hack is an Alix-1 which draws very little power but is fast enough to run a full Linux distribution system. To fit into a recess in the base of the RX-8 boot, a mounting frame was assembled. It has room to mount the Alix-1, a USB hub, a charge circuit, and a deep-cycle 28A/h sealed lead acid battery. The SLA battery i...

Have you ever connected two PCs together via modems using a twisted pair cable and nothing happened? That’s because the modems are expecting a phone line with all the signals and voltages supplied by the local telephone exchange. This circuit simulates the DC power and signal isolation but not the "dial tone" or the "ring signal". It suffices to connect two PCs together to communicate and exchange files using HyperTerminal. The circuit is self-explanatory and needs only one power supply for both modem lines. Although 50V DC is the usual exchange line voltage, this circuit should operate down to 20V. A 600O line transformer (eg. Jaycar cat. MM-1900) provides signal isolation, while the resistors provide current limiting and keep the lines as balanced as possible. Circuit diagram: How To Connect Two PCs Using Modems Circuit Diagram When using this set-up with HyperTerminal, you should not select a Windows modem driver in the "Connect To" dialog. Instead, con...

This is a water sensor /rain alarm circuit diagram; it can be used on motorcycle, car or other device that we want to protect from water, rain. This is a simple water sensor/rain alarm circuit that makes an alarm when water/rain falls on its sensor. This circuit is based on NE555/LM555 IC and two transistors (Q1&Q2). For transistor Q1- BC547 or BC107 and for Q2- 2N825,BC548 or BC168 can be used in the circuit.  This rain detector circuit can be supplied from voltage source of +9V-12V DC. The resistor 470K ohm is a POT/Variable resistor; it is used to adjust the sensitivity of water/rain sensor. Use a 8 ohm,0.5w-1W speaker to hearing better alarm. Less than 8 ohm speaker could be harmful for the IC 555.  Circuit Diagram of Water Sensor   We can make the water sensor as shown in the image (Fig-1) using aluminu m conductor like a naked wire . Here can be used other conductor but we suggesting to use aluminum.

Small DC motors are efficiently controlled using pulse-width modulation (PWM) method. The circuit described here is built around an LM324 low-power quad-operational amplifier. Of the four op-amps (operational amplifiers) available in this IC, two are used for triangular wave generator and one for comparator. Op-amp N2 generates a 1.6kHz square wave, while op-amp N1 is configured as an integrator. The square wave output of N2 at its pin 14 is fed to the inverting input (pin 2) of N1 through resistor R1. As N1 is configured as an integrator, it outputs a triangular wave of the same frequency as the square wave. The triangular wave is fed to pin 5 of op-amp N3, which is configured as a comparator. Small DC Motor Control Circuit Diagram : The reference voltage at pin 6 of the comparator is fixed through the potential divider arrangement formed by potmeter VR1 and resistors R4 and R5. It can be set from –6V (lowermost position of VR1) to +6V (uppermost position of VR1). The triangular w...

In this article we will discuss how can you make PCBs using Eagle Layout Editor 5.6 Freeware (PCB design). First of all Open Eagle , under Projects right click and then left click to New Project . Give a name to the new Project , for example ‘ example’ and then click Enter . Right click the example , you created, and select New and then board. We will design a simple led chaser using PIC16F84a micro-controller. Add the component needed for this circuit by clicking on ‘ADD’ icon from tool panel in left. After arranging the components we get the figure like this: You can also assign the name to the component by selecting ‘name’ icon and then chose the component which is to be named. Now select the ‘wire’ icon, and the color for wire (normally I chose red). After tracing select the ‘polygon’ icon and draw a polygon (across the whole circuit), after doing this click on ‘Ratsnest’ and you will get this: Now give the name to the polygon (for example Vcc,Vss et...

Laser torch-based burglar alarms normally work in darkness only. But this long-range photoelectric alarm can work reliably in daytime also to warn you against intruders in your big compounds, etc. The alarm comprises laser transmitter and receiver units, which are to be mounted on the opposite pillars of the entry gate. Whenever anyone enters to interrupt the transmitted laser beam falling on the receiver, the buzzer in the receiver circuit sounds an alarm. The range of this burglar alarm is around 30 metres, which means you can place the transmitter and the receiver up to 30 metres apart. Since the laser torch can transmit light up to a distance of 500 metres, this range can be increased by orienting the phototransistor sensor properly. To avoid false triggering by sunlight, mount the phototransistor sensor such that it doesn’t directly face sunlight.  Long-range Burglar Alarm Using Laser Torch The transmitter circuit is powered by 3V DC. The astable multivibrator built around tim...

There are components that have special characteristics , one of them is the 1N4148 diode , it is a diode High - speed , and its switching speed is 4th , its voltage is 100 V and current of 450 mA . It besides a diode 1N4148 is used as the temperature sensor , that due to its characteristics that cause it to change its resistance with temperature change . Of course it does not compare to a sensor like the LM38 , but for some circuits of low precision , which just need to know if an element is hot or cold it is very useful .   Temperature Sensor Circuit using 1N4148 diode Diagram Using the multimeter and the 1N4148 as a thermometer The scheme above is a circuit that measures the temperature in a simple manner using a multimeter. It uses 1N4148 diode , and VR1 and VR2 must be adjusted with a thermometer , and is more precise measurement . On the scale of the multimeter can be compared to the scale of degree...

The battery discharger published in this website may be improved by adding a Schottky diode (D3). This ensures that a NiCd cell is discharged not to 0.6–0.7 V, but to just under 1 V as recommended by the manufacturers. An additional effect is then that light-emitting diode D2 flashes when the battery connected to the terminals is flat. The circuit in the diagram is based on an astable multivibrator operating at a frequency of about 25 kHz. When transistor T2 conducts, a current flows through inductor L1, whereupon energy is stored in the resulting electromagnetic field. When T2 is cut off, the field collapses, whereupon a counter-emf is produced at a level that exceeds the forward voltage (about 1.6 V) of D2. A current then flows through the diode so that this lights. Diode D1 prevents the current flowing through R4 and C2. This process is halted only when the battery voltage no longer provides a sufficient base potential for the transistors. In the original circuit, this happened at abou...

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 Power Supply Electronic Circuit Project a very simple and high efficiency step-up dc dc converter circuit that require few external components can be designed using the LM2700 step-up DC/DC converter with a 3.6A, 80mohms internal switch and pin selectable operating frequency. 3-to-12-Volts Converter Circuit Diagram: With the ability to produce 500mA at 8V from a single Lithium Ion battery, the LM2700 is an ideal part for biasing LCD displays. The LM2700 can be operated at switching frequencies of 600kHz and 1.25MHz allowing for easy filtering and low noise. An external compensation pin gives the user flexibility in setting frequency compensation, which makes possible the use of small, low ESR ceramic capacitors at the output. This circuit can be used for handheld devices and some other portable applications . This step-up DC DC converter will provide a 12 volts DC output voltage from an input voltage range between 2.5 to 4.2volts .