New Circuits Page 142
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Nowadays, just about every house has an outside lamp with a motion sensor. Such a device eliminates the need to feel your way to the front door, and it apparently also scares away intruders. The only problem is that free-running dogs and cats in the....
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Operation is from a 12v or similar supply, and R1 can be changed if necessary for higher voltages. In this and similar circuits there is considerable latitude in the choice of values for positions such as C1. At B VR1 is a top cut control, and VR2 the volume....
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The Sparkfun Solid State Relay (SSR) Breakout Board is shown below. An SSR works like a relay but is built using semiconductors for switching. It will run off of mbed`s VU 5V supply and works with any mbed digital output pin. The schematic is shown below for....
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The objective of the circuit is to build an electronic dice based on the functions of a 555 timer integrated circuit that operates in the astable mode. LM....
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This circuit shows a DS1236 that is used to monitor and control the power-supply and software execution of a processor-based system, and to provide a pushbutton reset. When an out-of-tolerance condition occurs (when VCC is below 4. 5 V for 10% operation, or....
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This is an Infrared based Broken beam alarm to protect doors and entry passages. It gives a loud alarm when somebody crosses the Invisible Infrared barrier....
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Perhaps you might want to provide a little ALC feedback to your driver, or use signals from a directional coupler to drive power monitors or SWR lockout circuits. I use this modest little circuit to do these things; the basic idea is to use a microwave diode....
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The basic principle of the theremin is theheterodyne oscillator. When I started developing the Open. Theremin I knew that I needed a stable and reliable oscillator. So I searched the internet and found various schematics with different components. I built....
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The cardinal principle originally designed is, the temperature value that the one-chip computer gathers the temperature sensor real time and place is compared with thermostatical values presumed and dealt with. Thus control and keep the temperature value of....
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A simple calling bell circuit that can be used in small offices to call the office boy using an existing intercom system. The office boy can be called from up to nine locations where extension lines are installed. The system is connected to a dedicated....
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This diagram tells us about how to use L200 device for the speed control of permanent magnet motors. By means of R1 and R2, we can obtain the desired speed,....
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This is a universal 1 Watt RF class C amplifier that is ideally suited for low power FM transmitters. Input should be at least 100mW to achieve 1W output. It is recommended to enclose the amplifier in a metal case. Build your own Accurate LC Meter....
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This is an intercom circuit which use LM380 as the audio amplifier and 2 transistors as the microphone pre amplifier. The sound quality will be good enough with low cost building. This circuit consists of two identical intercom units. Each unit contains a....
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The prototype for this model is one of a `DSG` class of 24 locomotives built in 1981 by Toshiba for the New Zealand Railways. These locomotives weigh 56 tonnes and have two diesel engines, providing a total of 750kW. In more recent years they have been....
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Using TCM3105 FSK modem chip from Texas Instruments, you can easily build a Bell 202 or CCITT V23 compatible modem. This modem circuit is capable transmitting the data at 75, 150, 600, and 1200 baud, and receive the data at 5, 75, 150, 600, and 1200 baud.....
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XP-power plug, FU-fuse, ST-temperature control, T1-low-voltage transformers, S1, S2-door interlock switch, S3-threshold control switch, RT-thermal sensor, K1, K2-relay, EL- furnace light, M1-wheel motor, M2-fan motor, T2-high-voltage transformer, C-high....
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A 2 diode selector circuit if your primary voltage source is greater than the diodes turn on voltage and the input voltage of the second diode. Schottky diodes are recommended for both their low lower turn on voltage (typically 0. 4v) and high switching....
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This circuit is a toy to encourage young children to count. Power is turned on by switch S1, then S2 is closed. This makes nine LEDs flash slowly. S2 is then opened and the LEDs go out. Pressing push-button PB1 turns on a random number of LEDs - briefly -....
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This transmitter had its origins as a conventional shunt fed Hartley oscillator for 80 meters using a pair of 27 triodes connected in parallel; with 300 VDC on the plates of the 27`s, I was able to get about 4 watts output ( with decent stability ) for about....
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Hi there - i`m a newbie here so please be nice if I tread on any toes And please take a deep breath - I have a fair bit to say, so go get some popcorn ....
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A discrete oscillator circuit shown in the schematic diagram below is? a variable duty cycle and variable frequency oscillator, can be used to produce...
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The circuit generates square and triangle wave. I wonder if I can add a couple of diodes and a potentiometer to be able to skew between triangle-ramp/saw and change the duty cycle of the square wave Is it that simple..
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BR Communications (later merged with TCI to become TCI/BR, later bought by Dielectric Inc ) makes a line of chirp sounder transmitters and receivers. See my RCS-5 Chirp Sounder page for more on this. One of the features of the Chirp Sounder system is that a....
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This circuit takes two separate line-level stereo (L & R) signals and combines them into one stereo (L & R) output, thus avoiding the need to switch between two pairs of input signals. In the author`s application, it is used to feed the stereo audio from a....
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This circuit is made to be an alarm, both for home and handbags. If it is installed for home it will placed on door or windows, and if it is installed for bags...
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A circuit schemes basic heavy-duty electrical system which connecting components such battery, starting motor, alternator, magnetic switch, ignition switch, and connected wiring..
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This application note presents alternate RF matching networks for the MAX2653 SiGe LNA, tuned for the GPS band (1575MHz center frequency). Performance metrics (supply current, forward gain, NF, IIP3, reverse isolation and input/output return loss) for both....
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All car batteries have required a 12v battery charger. And this is also true of Marine, RV and Power Sports batteries. The high efficiency lead acid type batteries available today require more efficient charging techniques. The most important factors in the....
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This smoke detector is designed using 555 timer circuit and some common electronic components. The photo interrupter module is used as the smoke detector, while timer 555 is wired in astable configuration as an AF oscillator for sounding alarm via a....
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This 3 band equalizer circuit is an active filter network for bass, mid and high audio ranges. It is designed around the LM833 opamp from National Semiconductors. The output of this 3 way graphic equalizer is designed to be DC coupled, however due to slight....
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The first two are `passive` elements and op-amp is an `active` element. Also: the first two are `two-terminal` elements and the op-amp is a `three-terminal` element. Resistor has the ability to define the current that flows through it when a voltage is....
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a magnetic pickup from an old record player can make a great pressure, and vibration sensor. replace the needle with a plate of thin metal (copper off a pcb is good, ) and you`ve got an incredible touch sensor. use this circuit to amplify the circuit before....
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Designed for communications use, this equalizer circuit uses a Mitsubishi M5226P audio equalizer IC to adjust frequency response. It runs from a 9 to 20 V supply. C6 through C16 are polyester film capacitors of +- 5% tolerance. (QST, ..
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That simple 4 digits converter circuit has OUTPUT COUNT = 1 according to my f-IMHz to 10.000. All diodes are IN4146 `POLYSTYRENE` NPO. The circuit uses the LF398 at input..
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With this compact FM adaptor circuit plugged into the audio out of your cassete player or i Pod out put, you can listen your favorite music on your car stereo. This circuit is very useful if your car stereo doesnot have an auxillary in socket. The circuit is....
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For some time i wanted some way to measure laser power, without spending a fortune on a power meter. First off, it is not possible to build something....
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By using a simple visual indicating system, this small transistor tester allows you to run a quick go/non-go` check on NPN as well as PNP transistors. If the device under test is a working NPN then the green LED (D1) will‚ash, while the red counterpart....
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This high-performance video-camera link transmits signals from your video camera to your VCR, or from your VCR to TVs throughout your home. The first stage of the rf chain is a crystal-controlled oscillator, Q1, with a frequency of 60 to 65 MHz, which is....
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This schematic is modified from an old Bell & Howell projector amp for model 302 - PP 6v6`s with a 12AU7 PI. Can anyone identify the PI circuit It appears closest to "floating paraphase" to me. My only complaint with this circuit is that I`d like more clean....
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The TDA7294 is a Hi-Fi amplifier and can give 100W RMS but with 10% distortion. Supplying 30 Volts you can have 50 Watts RMS with 1% distortion. Frequency range start at 16Hz and can reach 100KHz. Make sure you are using good heatsink. The chip supports mute....
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This fire sensor circuit exploits the temperature sensing property of an ordinary signal diode IN 34 to detect heat from fire. At the moment it senses heat, a loud alarm simulating that of Fire brigade will be produced. The circuit is too sensitive and can....
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The first thing you must have in your workshop/lab is power supply. In experimenting many new electronic circuit design, it is easier if you have a flexible adjustable power supply. Here is an adjustable 0-30 volts power supply design. The circuit schematic....
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This simple device allows two computers to share a single USB printer or some other USB device, such as an external flash drive, memory card reader or scanner. A rotary switch selects the PC that you wish to use with the USB device, while two LEDs indicate....
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This counter uses a four-digit display, but with a flip of the range switch, it can display frequencies from 1 to 40 MHz, with a resolution of 100Hz. The MM74C926 CMOS IC contains a four-digit decimal counter that can latch a given count and then use this....
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The tuned circuits of capacity and inductance used in vacuum tube transmitter circuits are frequently called "tank" circuits, because from one viewpoint they act as tanks or reservoirs of RF energy. Blocking Capacitors. -Blocking capacitors are used to....
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Now a days most of the inverters available in the market utilizes the PWM(Pulse Width Modulation) technology. The inverters based on PWM technology are superior in many factors compared to other inverters designed using conventional technologies. The PWM....
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The need for a device that can detect and extinguish a fire on its own is long past due. Many house fires originate when someone is either sleeping or not home. With the invention of such a device, people and property can be saved at a much higher rate with....
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This is a motor speed control circuit that allows safe and easy control of 115VAC "universal motors" like drill motors, blender motors, other power tools, etc. The motor is controlled directly by a triac-diac component that is found in variable-speed....
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Using just two NAND or inverter gates its possible to build a D type (or toggle`)‚ip-‚op with a push-button input. At power-up the output of gate N2 is at a logical 1`, ensuring that transistor T2 is switched off. When the push-button is pressed the output....
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Both halves of the circuit are identical. Both inputs have a dc path to ground via the input 47k control which should be a dual log type potentiometer. The balance control is a single 47k linear potentiometer, which at center adjustment prevents even....
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Here is a simple circuit that can be used to pulse an LED or a low power filament lamp. The effect is such that the LED lights up from OFF state gradually and then dims gradually. Such a circuit is very useful in decoration purposes. The circuit is nothing....
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This is the simple and easy way to tap current from a Motor Bike battery to charge the Mobile Phone. Most of the Mobile Phone battery pack has three 1. 2 volt cells making the voltage to 3. 6 volts. For fast charging of the battery pack, each cell requires....
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The frequencies which are above to the limits of hearing are called Ultrasonic waves or frequencies, ultrasonic waves, piezo electic cell, Magneto Striation OSC, Piezo Electric OSC, Hartley OSC with piezo Cell....
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It`s enough to explore PWM and digital-to-analog conversion, and it illustrates how you can create your very own electronics workbench to explore RC filters , charge curves, discharge curves, pulse generators, timers, and even create a very simple....
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The following circuit shows about High Voltage, Low Current Supply. Feature: Used for (biasing of gas-discharge tubes, radiation detectors, etc), ....
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A motorcycle or boat battery that is not needed over the winter is usually charged before being put away for the winter, after which it remains standing unused for months on end. As a result, it accumulates deposits of lead sludge, which can result in....
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This PIC microcontroller tutorial provides a simple method to interface any keypad (e-g 4x4 or 4x3 etc) with PIC16F877 microcontroller. This code is writte....
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This IC is a wideband RGB Video Amplifier with DC control developed for monitors. It includes three matched video amps, a differential input Comparator for brightness adjustment, and three matched DC ....
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The Link Telephone Intercom. The Link circuitry is simple and efficient, employing just two ICs, half a dozen transistors, and a handful of garden variety components. It all runs on 12...
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Having a very healthy population of moles in our vicinity, I logged onto eBay and bought four of the cheaply available (ultra )sonic mole deterrents for our garden lawns in the hope of persuading them to move elsewhere. Here`s a link to a couple of similar....
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This humidity controlled switch circuit turns on and off an electrical load (for example a heater) depending on the moisture content of the surrounding air....
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This is a schmitt trigger circuit. This circuit produces a simple comparator action. It is `emitter coupled`. This circuit has a distinct hysteresis loop and....
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This the Good Quality FM transmitter for your stereo or any other amplifier gives you a pretty good signal strength up to a range of 500 metres having a power output of about 200 mW. This circuit can be operated with a 9V battery. The audio-frequency....
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Phase controlled AC voltage regulator, (a) Using back to back SCR and diode and (b) using inverse parallel SCR (c) Using diode-bridge and single SCR Figure 30. Input and output voltage waveforms for input 250V and output 300V. V1(V5): Input voltage- bottom....
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Charges and protects your mobile phone from voltage spikes and short-circuit Most mobile chargers do not have current/voltage regulation or short-circuit....
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This is circuit of Clap Triggered Switch. When the circuit detects tap, or short whistle or a clap, this circuit will toggle the LEDs. 33k and 5K6 charge The...
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This circuit turns-off an amplifier or any other device when a low level audio signal fed to its input is absent for 15 minutes at least. Pushing P1 the device is switched-on feeding any appliance connected to SK1. Input audio signal is boosted and squared....
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A 1984 F-350 crew cab w/a 460. My fuel gage does not work and it will not pump from the front tank, were do I start I have replaced the switch in the dash and the switch on the frame. I just turned it on and did not hear anything. The pigtail that goes into....
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The circuit a series of Dual Power Supply, where the symmetrical ± 15V supply for linear circuits. The same principle applies to supplies of non-symmetrical, such as 5. 0 V and-12V regulators for applications such as registers. To ensure start up LM340 over....
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This is a circuit to test zener diodes. It hooks up to a 120V AC line and boosts the output ....
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When you use microcontrollers in your designs, sometime you face a problem how to show user required data. Several LEDs, 7 segment display or LCD module can be solution. But if you must show a lot of information simultaneously, it can be difficulty. Large....
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A servo motor is a special geared DC motor equipped with an electronic circuit for controlling the direction of rotation, as well as the position, of the motor shaft. Because servo motors allows precise angular positioning of their output shaft, they are....
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I am attempting to design an alarm using a LM555 timer. I dont know where to start. My friends around have been designing them and I am trying to make ....
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The schematic diagram come from circuit: 12V DC Voltage Doubler Circuit power supply. Go to that page to read the explanation about above power supply related circuit diagram. This is the circuit diagram of DC voltage doubler / DC converter. The circuit will....
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Here is the circuit diagram of IC Controlled Emergancy Light With Charger or simply 12V to 220V AC inverter circuit. The circuit shown here is that of the IC controlled emergency light. Its main features are: automatic switching-on of the light on mains....
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With a rotary encoder we have two square wave outputs (A and B) which are 90 degrees out of phase with each other. The number of pulses or steps generated per complete turn varies. The Sparkfun Rotary Encoder has 12 steps but others may have more or less.....
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This is a starting method that reduces the starting current and starting torque. The device normally consists of three contactors, an overload relay and a timer for setting the time in the star-position (starting position). The motor must be delta connected....
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Electronic Design has a smart battery charger schematic using only a single transistor. This is interesting as similar circuits now contain simple integrated circuits. When the battery`s charge falls below a threshold voltage, it is automatically recharged....
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