Rongge

Circuit Diagram Description An reverse biased germanium diode is used here as a heat sensor at normal room temperature the reverse resistance of the diode is very high in the order of over 10 kilo ohms so it produce no effects on the transistor Q1 which conducts and keeps the reset pin 4 of ic 555 at its ground level, and so the alarm doesn’t get activated. When the temperature in the vicinity of the diode (the sensor) increases in case of fire, the reverse resistance of the germanium diode drops at about 70 degree its resistance drops to a value below 1 kilo ohms this stops Q1 conduction and the 555 ic pin 4 becomes positive through the resistor R1 which activates the alarm. Note: For installation of the alarm two or three reverse biased germanium diode can be connected in parallel at different locations in case of fire any of the diode can sense the heat and can activate the alarm. DR25 Germanium diode is recommended for use but still it can be replaced with base emitter junctions o

Desktop computer power supply - ATX type Delta Circuit diagram Click on the schematic to magnify

Here is a simple oscillator circuit that varies the duty cycle over a wide range without affecting the frequency. It is a variation of the simple 555 astable oscillator. Initially, I told a reader that there was no standard 555 circuit that could do this, but then the grey matter started working. The use of an air-variable capacitor for frequency control is a mind-blower—nothing short of a time warp! 555 Duty Cycle Control Schematic Overview When potentiometer R1 is centered, operation is obvious and the duty cycle is 50%. However, as R1 is rotated in either direction the charge time and discharge times vary accordingly. The two sides of R1 have independent steering diodes (D1 & D2). C1 & C2 make up the timing capacitor. Pins 2 & 6 of the 555 are the upper and lower thresholds of the input comparators. The charge /discharge voltage is taken from pin 3 because it has rail-to-rail voltage swing, and the open collector output (pin 7) cannot do this. The rectangular waveform o

This post share about Mobile Phone charger circuits, previously you can see other Phone Battery Charger Circuit   or Charger Circuit  . This Charger ciruit use to charging phone battery using IC 7805 for plus voltage regulator or & 7905 for min voltage regulator.  Below is a schematic circuit adapter, power supply , or battery charger (for gadgets, mobile phones , MP4player, smartphone) that is equipped with a 5V voltage stabilizer : Diode Bridge diode bridge, known as a diode bridge is used for the rectifier circuit current ( rectifier ) from AC to DC . to make the diode bridge properly you need to know the type of diode to be used, to suit your needs. example: to make the power supply 12 Volt 3 ​​Ampere diode type 1N5401 is needed, for more detail how to choose the right type of diode to the adapter. Voltage stabilizers are commonly used are the 78XX or 79XX type LM, XX indicates the maximum voltage output is generated. see the example in the circuit schematic above, to outp

A photodiode Dl feeds high gain IR remote control preamp 1C, a CA3237E. U2 is a PLL FM detector tuned to around 100 kHz. The detector output is amplified by U3 and it can drive a speaker or a set of headphones. Wireless IR Headphone Receiver Circuit Schematic

2.3 Occupational Information Network Key Points 1.         The four major groups of occupations in the field of electrical engineering are: a.         Power engineering b.        Electrical installations engineering c.         Communications electronics engineering d.        Industrial electronics engineering. 2.         Across the network of technical occupations, the following personnel cadre are employed: a.         Artisan b.        Craftsman c.         Technician d.        Engineer. 3.         An artisan is an accomplished operator with a comprehensive knowledge of techniques and the tools used in his or her area of specialty. 4.         A craftsman is a skilled individual talented to perform a range of tasks in his specialty to the required standards. 5.         A technician is a highly skilled worker with both theoretical and practical backing. A technician is directly answerable to the engineer or a technologist. 6.         An engineer is the topmost head of technical teams in

Circuit Description: Ever Imagined controlling your home appliances using your cell phone. You can find a lot of circuits for this application. But they make use of Telephone. I modified the circuit and redesigned it to make it compatible with normal cell phone headphone. Just connect the your phone headphone jack to the phone and the connections to the circuit as shown in the circuit. The relays are connected using the resistor and transistor. Use ULN2803 to reduce the circuit size and increase the performance. The connections from the output of flip-flops has to be given to the inputs of the buffer and relays has to be connected to the buffer. Normally the tip of the headset is connected to the circuit to the 0.1uF capacitor as shown in the circuit diagram. The ground pin of headphone is connected to the ground of the circuit. Circuit Diagram: Operation: When you press keys in your Phone, the other person will hear some tones with respect to keys pressed. This tones are based on the

Here is an interesting circuit , it is used to make a kind of lock or locks for bicycles , it allows owners to implement a bicycle lock and electronic alarm with a low cost . The operation of the electronic lock is simple , it has a circuit that uses a tone generator IC UM3561 , this IC generates a sound when your bike has the protection wire that surrounds the wheel broken .   Blocking Circuit with Alarm for Bicycle Circuit Diagram Click here to download complete project

This is a project os Model Railway Short-Circuit Beeper Circuit Diagram . Short circuits in the tracks, points or wiring are almost inevitable when building or operating a model railway. Although transformers for model systems must be protected against short circuits by built-in bimetallic switches, the response time of such switches is so long that is not possible to immediately localise a short that occurs while the trains are running, for example. Furthermore, bimetallic protection switches do not always work properly when the voltage applied to the track circuit is relatively low.  Model Railway Short-Circuit Beeper Circuit Diagram The rapid-acting acoustic short-circuit detector described here eliminates these problems. However, it requires its own power source, which is implemented here in the form of a GoldCap storage capacitor with a capacity of 0.1 to 1 F. A commonly available reed switch (filled with an inert gas) is used for the current sensor, but in this case it is actuat

Controlling temperature has been a prime objective in various applications including refrigerators, air conditioners, air coolers, heaters, industrial temperature conditioning and so on. Temperature controllers vary in their complexities and algorithms. Some of these use simple control techniques like simple on-off control while others use complex Proportional Integral Derivative (PID) or fuzzy logic algorithms. In this project Shawon Shahryiar discusses about a simple control algorithm and utilize it intelligently unlike analogue controllers. Here are the features of this controller: Audio-visual setup for setting temperature limits. Fault detection and evasive action. Temperature monitoring and display. Audio-visual warning. System status. Settable time frame. Data retention with internal EEPROM memory. [ ]

This is an economic circuit of a mini solar lighting system, solar panel 6V/2W is used to charge a rechargeable 4V/800mAh through a current limiting circuit load that uses a LM317T adjustable regulator 3 pin (IC1). Assuming a sunny day 6 hours, a panel will enviarr 2 watts for approximately 900mAh battery. The current can be reduced by increasing the value of R1, for example, 8.2 to 10 ohms ohms.   Lighting Garden with Solar Energy Circuit Diagram Specification of a typical solar panel  6V/2W:Maximum power (Pm):  2WWorking Voltage (Vmp):  9VWorking Current (Imp):  220mAOpen Circuit Voltage (Voc):  10.5VPower Tolerance: -3% to 5%

This is the best IC LA 4440 Laptop Audio Amplifier circuit diagram, the audio output from the laptop’s built-in loudspeakers is low. A energy amplifier is needed to obtain a high volume. This is a simple circuit to amplify the laptop’s audio output. The circuit is made around energy amplifier IC LA 4440 (IC1) along with a couple of other components. LA4440 is really a dual funnel audio energy amplifier. Circuit diagram : Laptop Audio Amplifier Circuit Diagram It’s low distortion over an array of low to high wavelengths with good funnel separation. Built-in dual channels enable it for stereo system and bridge amplifier programs. In dual mode LA4440 gives 6 w per funnel as well as in bridge mode 19- watt output. It’s ripple rejection of 46 dB. The audio result can be recognized by utilizing two 6-watt loudspeakers. Connect hooks 2, 6 and ground of IC1 towards the stereo system jack which is combined with laptops. Assemble the circuit on the general-purpose PCB and enclose inside a

Because I’m old school, I wanted to build a Garage Door Closing circuit without relying on integrated configurations (555 timer etc) to keep it simplistic. The circuit closes the garage door after two minutes with C3 and four minutes with the addition of C2. The timer relay is surprisingly accurate (+/- five seconds). Another feature is to ensure that the garage door actually did close, such as if it’s stopped mid-operation by the user. S3 (magnetic N.C.) is located at the garage door and activates the circuit when the garage door opens. RL1 is the reset timer. It’s maintained in the “on” position for two minutes by C3 while the trigger capacitor, C4, is charged. RL2 is the conduit, directing C4 to either RL3 or R1 to ground when off. Purpose of R1 is to prevent arching across contacts and a fast discharge. RL3’s contacts are connected to the Garage Door’s Momentary Switch and is sustained “on”  for a half second by C5. When C3 discharges to the cutoff voltage of RL1, it turns off and

Most cars do not have delayed interior lights. The circuit presented can put this right. It switches the interior lights of a car on and off gradually. This makes it a lot easier, for instance, to find the ignition keyhole when the lights have gone off after the car door has been closed. Since the circuit must be operated by the door switch, a slight intervention in the wiring of this switch is unavoidable. When the car door is opened, the door switch closes the lights circuit to earth. When the door is closed (and the switch is open), transistor T1, whose base is linked to the switch, cuts off T2, so that the interior light remains off. When the switch closes (when the door is opened), the base of T1 is at earth level and the transistor is off. Circuit diagram: Capacitor C1 is charged fairly rapidly via R3 and D1, whereupon T2 comes on so that the interior light is switched on. When the door is closed again, T1 conducts and stops the charging of C1. However, the capacitor is discharge

Circuit Diagram Description In a recent article, I discussed the difference between parallel and series telephone taps. In this article, I present a very simple and reliable parallel phone tap circuit useful for recording telephone conversations onto a tape recorder. When installing a telephone tap, its advisable not to cut the telephone line in anyway. Cutting the telephone line for any time is detectable, and therefore series devices can be detected in this way. Parallel devices can be installed without cutting any telephone wires, and is thus harder to detect. The diagram shows a simple circuit using just 6 very cheap and common components. To build the circuit, you will need some Veroboard or prototype board (whatever you favourite is), some wire, and a 3.5mm plug that will connect to your tape recorder’s microphone input socket. I have left it to the reader to work this bit out, as its very simple to do but quite awkward to explain!   Source: http://www.spyreview.co.uk/2006/10/08/

Try to lighten up you PC by using LED flex lights to surround the casing. The result will be much appreciated when the room is dark. The chain is housed in rubber plastic which makes more light to be projected out right angles as if some miracle is happening inside the PC. You can choose which color to use or what you wish to blend with the design of your room. The LED strips are very flexible and customizable which makes them popular. It is very easy to install these strips by using Velcro strips of adhesive backing. You may also use the LED strips in any part of your room like the hairdresser mirror. Click here to visit the project page. Source by : Streampowers

The objective of the circuit is to create a power supply that would produce an output of 0 V to 15 V at 1 A current. Terminology 2N3055 – a complementary Silicon Epitaxial-Base planar NPN transistor mounted in Jedec TO-3 metal case for use as power transistor Bridge Diode – also known as bridge rectifier which has four diodes arranged in a bridge configuration where the output voltage has the same polarity with either polarity of the input voltage Circuit Explanation The construction of this power supply circuit is very simple in such a way that the components used are easy to be located while the cost is very cheap. With the biggest provided current at 1 A, the output voltage is adjusted for minimal ripple effect and stabilized in the range of 0 V to 15 V DC. This is made possible by the standard transformer output of 1.5 A with a primary winding voltage of 220 V and secondary voltage of 18 V. The current is being limited by the Zener diode D1 with a rating of 18 V and 1.5 W. The li

The current drain of the regulator is minute compared with that of, say, a 78L05: at an input voltage of 9 V and open-circuit output, it is just under 50 µA. The circuit consists of a straightforward bandgap reference based on T1 and IC1, followed by an amplifier formed by IC2 and T1. The reference voltage is about 1.22 V, which is raised by IC2 to 5 V. The output voltage can be set to exactly 5 V with P1. The input voltage may lie between 6.5 V and 30 V. The maximum output current with the present configuration and component values as specified is about 10 mA. For optimum performance, T1a and T1b need to be identical, which is why a dual transtor Type MAT02 is used. Other types that may be used are the MAT01, SSM2210 or LM394. In principle, two standard BC transistors may be used, provided they are selected for identical threshold voltage. Circuits IC1 and IC2 are programmable op amps Type OP22. In the case of IC2 this has the benefit that the peak output current can be set readily by

This simple water level sensor circuit monitors the presence of water in a certain location or container. The circuit sends an acoustic alarm when it senses a drop of water leak. It is very simple to build and it is made of a single IC and some passive components. Check out the water level indicator circuit too! The IC LM1801 is a low power comparator that can deliver high output current if needed. When water hits the sensor, the reference voltage is overshot and the IC drives the ceramic transducer to beep. It is also possible to connect several sensors to the water level monitor circuit. The sensor can be easibly made out of a small piece of PCB that is etched with the proper pattern. The decoupling capacitor C3 is a 100uF/16V electrolytic capacitor.  source [link] 

Tandem Doorbell Circuit Diagram .The author had a problem: the neighbors  had exactly the same type of doorbell as he did (actually a 50 Hz buzzer), so it wasn’t always clear who needed to answer the door. To avoid confusion, the author augmented the existing doorbell with a wireless model a reasonably inexpensive option at current  prices. All that was necessary for this was to arrange for the existing button and wiring to also actuate the wireless doorbell.  Tandem Doorbell Circuit Diagram The author opened up the button enclosure of the wireless doorbell and used a multi-meter to find out which set of contacts were closed when the button was pressed. This is where the relay output should be connected (see the schematic diagram). The circuit is virtually self-explanatory: when the existing doorbell button is pressed to actuate the  buzzer, the voltage is rectified by the bridge rectifier and regulated at 5 V by the 7805. This voltage drives the relay directly, causing the switch in th

This will flash a LED, employing a single 1.5v cell. it's going to even flash a white LED even supposing this kind of LED needs regarding three.2v to 3.6v for operation. The circuit takes regarding 2mA however produces a really bright flash. LED on 1.5v SUPPLY A red LED needs regarding one.7v before it'll begin to illuminate - below this voltage - NOTHING! This circuit takes regarding 12mA to illuminate a red LED employing a single cell, however the fascinating feature is that the approach the LED is illuminated. The 1u electrolytic may be thought of to be a 1v cell. (If you wish to be technical: it charges to regarding one.5v -0.2v loss as a result of collector-emitter = one.3v and a lost of about 0.2v via collector-emitter in diagram B.) It is firstly charged by the 100R resistor and therefore the third transistor (when it's totally turned ON via the 1k base resistor). this is often shown in diagram "A." throughout this time the second transistor isn't turne

The circuit above is a dummy load capable of handling up to 10 watts of RF power for a few minutes, and its impedance is 50 ohms. It is constructed with 10 parallel resistors 560 ohms per 1 watt, R1 to R10, a voltage divider R11-R12 and a rectifier D1-C1. Its output voltage in a voltmeter which can be connected to measure the RF power.

Watching movies is a neat escape from the stressful lifestyle we live in. Watching movies in a wide screen and surround sound take you far away and into the movie scene you are watching. You watch it as if you were there in the movie scene. Of late, we can only experience this escape in a cinema. However, modern technology may be able to provide this same sight and sound experience right in your own living room. We will discuss the basic components of a home theater system in this article. Read on to understand how these basic components can deliver the best cinematic experience to a home theater system. Home theater experts state that the most important consideration in setting up a home theater system is the size of the room where you will set up the home theater system. The most important component of the home theater system, which is the television, is dependent on the size of the room. Although, the recommendation is 27 inches television set at a minimum is necessary for your home

By organizing the annual CES 2010, Pass Laboratories has recently introduced a new device that is X260.5 mono-block power amplifiers. X260.5 offers a power output of 260W and comes with the Super-Symmetry topology features that can improve performance by adjusting the characteristic value of balancing and damping amplifier distortion / interference. X260.5 device brings all the sonic advantages of mono-block operation for A / B high-power amplifiers in a physical package that can be managed device is half the physical size and weight of the device X600.5 Class D mono-block power. Simple physical size, weight that can be managed and high strength coupled with great performance make this device as the Pass Laboratories ideal power-amp in any system that refers to a 2-channel and multi-channel format. In addition, it also brings flexibility X260.5 combination for consumers who already have a device Pass Laboratories Stereo amp and want to add an additional channel power amplifier that is

Battery-backup converter with one NiCd cell Notebook computers and added carriageable accessories generally use a advancement array to absorb anamnesis accommodation during advancement of the capital battery. Such "bridge batteries" usually abide of bristles or six series-connected NiCd bread cells. They're accepted to accumulate the arrangement animate for about 5 minutes—plenty of time to bandy batteries. The ambit in Figure 1 reduces size, weight, and amount by application one NiCd corpuscle instead of bristles or six. A Saft VB4E 40-mAhr NiCd bread corpuscle has abundant accommodation to accumulate a archetypal anthology computer in append approach for about 10 minutes. All apparatus (excluding the bread cell) absorb beneath than 1/2 in.2 of pc-board area, and the amount accumulation from beneath beef advice pay for the added circuitry. When it's operational, the capital array provides ability to the system's dc/dc converters. The LT1304 addition advocate con

Rechargeable torches don’t come without problems. You need to replace the bulbs and charge the batteries frequently. The average incandescent light-emitting diode (LED) based torch, for instance, consumes around 2 watts. Here’s a rechargeable white LED-based torch that consumes just 300 mW and has 60 per cent longer service life than an average incandescent torch.  Rechargeable Torch Based on White LED Circuit Diagram Fig. 1 shows the circuit of the rechargeable white LED-based torch. The reactive impedance of capacitors C1 through C3 (rated for 250V AC) limits the current to the charger circuit. The resistor across the capacitors provides a discharge path for the capacitors after the battery is charged. The red LED1 indicates that the circuit is active for charging. The torch uses three NiMH rechargeable button cells, each of 1.2V, 225 mAH. A normal recharge will take at least 12 hours. Each full recharge will give a continuous operational time of approximately 2.5 hours. Recharge the

This is the Simple Overtone oscillator with crystal switching Circuit Diagram. The large inductive phase shift of LI is compensated for by Cl Overtone crystals have very narrow bandwidth;, the re fore, the trimmer has a smaller effect than for fundamental-mode operation.  Simple Overtone oscillator with crystal switching Circuit Diagram

A very simple fluid lever sensor can be designed using this circuit diagram . This fluid level sensor electronic circuit project is very simple and can be used to control water pump or to activate /stop some devices when the sensor detects presence of water. Simple Fluid Level Sensor Circuit diagram This fluid level sensor circuit uses an ac sensing signal to eliminate electrolytic corrosion on the probes .The ac signal rectified is used to drive T1 transistor that drives a 12 volt relay , that can activate or stop some device . R2 resistor is used to modify the sensor sensitivity and can be replaced with a small variable resistor . MC104093B is a p channel quad 2 input NAND schmitt trigger and is pin to pin compatible with the CD4093 . The unused inputs must be tied to an appropriate voltage level , either ground or +12 volts (8,9,12 and 13) and the unused outputs must be left open (10 and 11) . The circuit can be powered with an input voltage between 3 and 18 volts dc , but in our ca

How to build a automatic lighting controller circuit. The governor following is intended to regulate the light intensity incandescent 220 V. The components in a relatively few, which means it can easily be mounted onto a small plate. After the build, we recommend you place it inside the box which is flush mounted switch ON / OFF the lamp. Setting the switch to ON, the lamp will light after about 400 msec, a delay is probably negligible. Automatic Lighting Controller Circuit Diagram: But when the state enters the ON OFF, then mesolathei a period of 20 sec, the brightness of the lamp remains unchanged to start falling out soon after.  The last feature is particularly useful when we want to have a little time from the moment you 'close' switch. Once the switch S1 set to ON, the capacitor C2 begins to charge through R1, C1 and bridge D1-D4. The Zener diode D5 limits the voltage across the capacitor to about 15 n. After awhile, the diode D6 LED illuminates, causing the appearance of

Activity diagrams are the object oriented equivalent of flow charts and data flow diagrams from structured development Activity diagrams describe the workflow behavior of a system The process flows in the system are captured in the activity diagram Activity diagram illustrates the dynamic nature of a system by modeling the flow of control from activity to activity An activity diagram contains activity states. An activity state represents the execution of a statement in a procedure or the performance of an activity in a workflow An activity state waits for the completion of its computation. When the activity completes then execution proceeds to the next activity state within the diagram When to use Activity Diagrams?  a complex operation  a complex business rule  a single use case  several use cases  a business process  software processes element of activity diagram

This is the Simple UPS Power Supply Circuit Diagram. This circuit is a simple form of the commercial UPS, the circuit provides a constant regulated 5 Volt output and an unregulated 12 Volt supply. In the event of electrical supply line failure the battery takes over, with no spikes on the regulated supply. Notes: This circuit can be adapted for other regulated and unregulated voltages by using different regulators and batteries. For a 15 Volt regulated supply use two 12 Volt batteries in series and a 7815 regulator. There is a lot of flexibility in this circuit. TR1 has a primary matched to the local electrical supply which is 240 Volts in the UK. The secondary winding should be rated at least 12 Volts at 2 amp, but can be higher, for example 15 Volts. FS1 is a slow blow type and protects against short circuits on the output, or indeed a faulty cell in a rechargeable battery. LED 1 will light ONLY when the electricity supply is present, with a power failure the LED will go out and outp

Overview: The AN7510/7520 series is a 0.5W to 3W BTL audio power amplifier IC. Equipped with a standby function and mute or DC  volume circuit, the series includes a lineup of single and dual output models. With simplified set design due to minimum  external components, this IC has a wide variety of applications. Features: Operating power sourcs voltage: 3.0V to 13.5V. Built-in standby function. Built-in mute or DC volume circuit. Circuit Diagram:  0.5W to 3W BTL audio power amplifier IC

Build a 3 volt to 9 volt with LMC555 Circuit Diagram. This is a Build a 3 volt to 9 volt with LMC555 Circuit Diagram. This dc converter is built with the CMOS version of 555 timer. You can get 12V too if you change the zener diode to a 12V version. 3 volt to 9 volt with LMC555 Circuit Diagram

This is the simple Fan Speed ​​Control for Temperature Circuit Diagram. With this simple circuit that you will be able to control the speed of a DC fan according to the temperature measured by a temperature sensor. It is an ideal accessory for your projects that require cooling that are not constant.  This simple design allows precise speed control of motors, fans, and blowers, proportional to the temperature. An NTC thermistor (R1) is used as temperature sensor. A circuit optional was added to remotely monitor the operation of the fan and to allow some kind of indication of the approximate speed by increasing the brightness of an LED.  Fan Speed ​​Control for Temperature Circuit Diagram The R5 must be configured to allow the engine just starting to run at the desired temperature. Any 6K8 between the NTC thermistor 22K can operate provided that the R2 value is one tenth of the thermistor. R6, R7 and D1 are optional: R7 obligation is adjusted until the LED glow dimly when the engine is

Function Capacitors store electric charge. They are used with resistors in   timing circuits   because it takes time for a capacitor to fill with charge. They are used to   smooth   varying DC supplies by acting as a reservoir of charge. They are also used in filter circuits because capacitors easily pass AC (changing) signals but they block DC (constant) signals. Capacitance This is a measure of a capacitor's ability to store charge. A large capacitance means that more charge can be stored. Capacitance is measured in farads, symbol F. However 1F is very large, so prefixes are used to show the smaller values. Three prefixes (multipliers) are used, µ (micro), n (nano) and p (pico): µ means 10 -6  (millionth), so 1000000µF = 1F n means 10 -9  (thousand-millionth), so 1000nF = 1µF p means 10 -12  (million-millionth), so 1000pF = 1nF Capacitor values can be very difficult to find because there are many types of capacitor with different labelling systems! There are many types of capacit