Popular Circuits Page 192
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Telephone Headgear. Acompact, inexpensive and low component count telecom head- set can be constructed using two readily available transistors and a few other electronic...
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This project was a particular surprise for me in that the BC547 (equiv 2N2222) can be used to build a 500mW linear amplifer covering the entire HF band with excelent spectral purity and no neutralising at all. Ugly-bug construction was used but I dare say....
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Preamps may in some cases use a simple regulator, with the supplies taken from the main amp power supply. This can be a problem if the main amp is of very high power, as the supply voltage will be too high for 3-terminal regulator ICs. This will also be a....
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Adjustable Regulated Power Supply 0-15V 1A. Adjustable Regulated Power Supply 0-15V 1A. The output voltage is stabilized and regulated in the range of 0V to 15 V, supplied with a maximum current of 1A. The schematic diagram come from circuit: Adjustable....
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This is a very simple 5 watt CW TX based upon a TTL logic chip. There is just one "tricky" component and this is Cx. This component should have an impedance of about 10 - 50 ohms at the frequency of interest. If you wish to reduce the transmitter power,....
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You`ve probably heard about the CP210x USB ICs from Silicon Labs, now here`s an application that uses it. The CP2102 gives us 3V TTL to a VCP (virtual comm port) over USB as well as generating the 3. 3V needed for the board. There are a couple things to....
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In this circuit the 555 timer is used in a novel way, as a voltage controlled switch.The old and omnipresent NE555 can be very good at someth....
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The MP-P2 Power Supply is the supply designed to power the mother board and its complement of plug-on boards including the MP-09 Microprocessor Board, disk controller board, memory boards and up to eight interface boards on the SWTPC Computer system. It....
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The following circuit shows about Installing Bathroom Electrical Wiring Circuit Diagram. Features: safety, energy saving, increase your home ....
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Using the LTC3810-5 synchronous step-down switching regulator controller can be designed a very easy and simple 12 volt switching power supply electronic project using few external electronic parts. LTC3810-5 synchronous step-down switching regulator....
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This FM oscillator can be used for wireless audio, microphone and part-15 applications where stable frequency modulated oscillators is needed. Lt can be va....
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No description available...
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A high speed oscillator is possible by combining an MECL 10 crystal oscillator with an MECL III frequency doubler as shown. One section of the MC10101 is connected as a 100 MHz crystal oscillator with the crystal in series with the feedback loop. The LC....
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The TV transmitter circuit given here uses UK standard 1 FM modulation for sound and PAL for video modulation. The audio signal to be modulated is pre-amplified using the transistor Q1 and associated components. The transistor Q2 has two jobs: production of....
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This project shows you how to build simple flashing light based on IC 555. The 555 has function as clock generator with dutycyle less than 100 and more than 50. The other components are Voltage regulator, 3 power amber LED and passive component like resistor....
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GVI Digital Remote Control for DSLR camera is a step forward from my previous remote control for Canon EOS 450D. This remote is based on AVR Microcontroller ATmega328 and is programmed using Arduino IDE GVI Digital Remote Control is a tool for photographers....
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This new FM transmitter is very easy to make and doesn't need any RF tuning. First of all ,we have used an integrated VCO: The POS150 from Mini-circuits. This excellent RF circuit covers all the FM Band in a voltage range of 4V to 8V. The Kvco factor is very....
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A simple fire alarm circuit based on a LDR and lamp pair for sensing the fire. The alarm works by sensing the smoke produced during fire. The circuit produces an audible alarm when the fire breaks out with smoke. When there is no smoke the light from the....
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It incorporates a Starter for each lamp, which heats up the fillaments [Cathodes] at each end of the lamp prior to starting. Once the lamp has started, it no longer requires heated fillaments. The heating is only a starting aid. During normal operation, the....
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This circuit is often used by amateur radio operations, shortwave listeners, and other operators of shortwave receivers to calibrate the dial pointer. The oscillator operates at a fundamental frequency of 100 kHz, and the harmonics are used to locate points....
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This RS232 power supply circuit diagram is an simple RS-232 Line Driver Power Supply, that operates from an input voltage as low as 4. 2V, and delivers an output of ±12V at ±40 mA with an efficiency of better than 70%. This RS232 power supply circuit....
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It started out as a simple unenclosed variac (variable autotransformer) and electrical outlet mounted on a block of wood. I eventually put it in the case of what used to be an old audio signal generator for safety and appearance. Among the other added....
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This circuit produces a pure, - 80-dB THD sine wave with a frequency that is equal to the fc of IC3"s filter. A TT..
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Colpitts oscillator circuit diagram and theory. Colpitts oscillator frequency equation. Colpitts oscillator using transistor. Colpitts oscillator using opamp....
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Discrete components ultrasonic transmitting circuit T / R-40-16 can emit a series of ultrasonic signal of 40kHz. ..
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Under good battery conditions the LED is off. As the battery voltage falls, the LED begins to flash until, in the low battery condition, the LED lights continuously. Designed for a 9-volt battery, with the values shown the LED flashes from 7.5 to 6.5 volts.
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You will be reading input from a keypad and display the corresponding button pressed unto a 7-segment display. You will be required to write a C program which will determine which key has been pressed on the key pad. The program will then display the....
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The circuit uses a NTE1690 DTMF dialer chip and a PIC16F690 microcontroller. Because this is an IP phone and I cannot just send the DTMF tones over the line, the easiest place to plug in the box is between the phone and the handset. The box has two RJ9 ports....
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A XICOR X9241 POT IC module can be used to adjust the four digital analog circuits, as shown in the schematic. ..
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For some applications it is important to have a tone decoder with narrow bandwidth and fast response time. This can be accomplished by the dual time constant tone decoder circuit shown. The circuit has two low-pass loop filter capacitors, C2 and C'2. With no....
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By means of a Relay, employed to drive a water pump, this circuit provides automatic level control of a water reservoir or well. The shorter steel rod is the water high sensor, whereas the longer is the water low sensor. When the water level is below....
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BEAMSonics is a clever little circuit designed by Wilf Rigter. It`s central function is to filter incoming sounds and count high pitched pulses, whistles, beeps etc. When it hears a certain number of beeps it will respond with a noise of its own. If left on....
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This Idea for Design describes a 12-V dc to 5-V dc (±5%) switched-mode power supply (SMPS). The supply uses a 12-V input from an array of four 3-V dc, 40-mA solar cells connected in series..
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That`s a great idea to use the chips internal reference and some resistance to get the right bias on the audio; it would really reduce the parts count ..
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Butterworth filter is a filter whose freq response is flat over the passband region. British engineer Stephen Butterworth first described this ..
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Before I begin talking about the schematic, let it be known that there are four hardware blocks to this circuit: 1) The wall transformer 2) The charge....
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A couple of years ago I decided I would (eventually) need to replace my decades-old Nakamichi stereo with something more suited to a mobile lifestyle. It was immediately pretty obvious that the Class-D and E switching amplifiers I had researched in the `70s....
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If you`ve ever wondered how electronic devices like computers can count, this article gives a simple introduction to binary and logic and shows how they are tied together with electronics to make both simple and complex computers. Please note: There are a....
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The coil is about 25 turns #28 wire on a T-44-6 core, tapped at about 5 turns. I'm too lazy to open my VFO and count it for you -- besides, you'll probably have to tweak it yourself with your available components. Once the turns are squeezed to the right....
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This is a one of the light sensor. This circuit is a dark sensor that is based on op amp 741 IC as main control. This circuit is a simple design for sensor the light at the night. This is the figure of the circuit. For sensor the light is using LDR.....
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Here is a very simple three transistor audio amplifier circuit that can deliver 250mW to a 8Ohm speaker. Complementary transistors BC337 and BC227 (Q3 and Q2) are used as the output pair. Transistor Q1 (BC 547) acts as the preamplifier. POT R5 can be used as....
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This is an image Schematic. No Description available...
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Audio graphic equalizers are very common as commercial products (for Hi-fi, car audio and stage use) but circuits for them are very rarely published. I didn`t design this one but it`s really very simple. The details shown are for a 7 band but the principle....
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Power supply: 12-14 V stab., 100 mA. RF power: 400 mW. Impedance: 50-75 ohm. Frequency range: 87,5-108 MHz. Modulation: wideband FM. Connect the 6 V / 0,1 A bulb to the output and use R1 to tune the right frequency. Maybe you might stretch coils of the L1.....
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This project is one for the experimenter, but as shown will work extremely well. The sensing circuit can be made so sensitive that a load of only 2.5mA is enough for the circuit to detect, and disconnect the charger.
The idea is that the charger is left....
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A good thing too since I initially hooked the p-channel mosfets up backwards. No smoke fortunately. I`m using Pololu gear headmotors (although continuous rotation servos will also be supported). In order to drive the motors in either direction I`m using....
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DIY Homemade Plasma Gun. Awesome DIY project showing how to make a real working Plasma gun! The plasma gun is based on a small Tesla coil....
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The question sometimes comes up of how to cascade 4017 decade counters for more than 10 sequencial stages. The LED sequencer below shows a possible solution using a few extra parts. When power is applied, the 15K resistor and 10uF cap at pin 15 will reset....
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Various embodiments of the BB metal detector have been published, and it has been widely described in the press as a new genre. Instead of using a search and a reference oscillator as with BFO, or Tx and Rx coils as with IB, it uses two transmitters or....
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In October of 1958 when this article was written, a mere year had passed since the successful launch of Sputnik and a few months later the launch of Echo satellites - the first ever for Russia and the USA, respectively. Prior to that time all satellites were....
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Enhancement circuit as shown in the high-frequency component of the video signal can be increased, thereby enhancing the contrast of the TV image, it can also be connected to t..
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Here is a solar charger circuit to charge Lead Acid or Ni-Cd batteries using solar energy. The circuit harvests solar energy to charge a 6 volt 4. 5 Ah rechargeable battery for various applications. The charger has Voltage and Current regulation and Over....
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The Over-the-Top type of operational amplifier is ideal for use as a current sense for battery charger applications. The design described here can be used....
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This is a slightly revised version of the 6-transistor H-bridge designed by Mark Tilden and found on the BEAM Tek website (now only available via archive).
I encourage anyone interested in H-bridges to read Mark's article, as it gives an excellent....
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This project really works with water. I don`t know how can I use this but you know that I like those stuff. I started my tesla coil too but I don`t think that this stuff will work. from a conventional transformer in that the voltage and current relationships....
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AC power supply voltage is normal, relay, connected to the load (Rfz) circuit. When the load short-circuit failure, KA voltage drop across quickly, KA release, cut off the load..
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The purpose of this circuit is to automatically turn off any device plugged into its power outlets after a certain period of time. Shutoff is activated by an absences of an audio signal or by a standard timer function. This unit would be connected to speaker....
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When the oscillator starts up, Q2 is conducting; the current comes from the capacitor, charging it until the voltage across it is large enough to get a current across the inductor. As the current across the inductor peaks, the output voltage rises (the....
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As shown in FIG circuit, T is auto voltage regulator. Its output fixed input end by a servo motor to automatically adjust the output remains constant.Transistor VTl, VT2: 3DK9C, = 65 ~ 85; VT3: 3AX818, = 60 ~ 80; diode VD2, VD3, VD6 ~ VD9: 1N4002; VD4,..
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This circuit de-energizes a normally energized relay if the input voltage goes above or below two individually set voltages. The transistor driving the relay is normally turned on by R4, so the relay is normally energized. Ifthe cathode of Dl or D2 is....
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This circuit is a simple 8-bit analogue to digital converter circuit which is connects to PC serial port. The circuit is based on TLC548 A/D-converter chip (might be hard to get nowadays, Texas Instruments makes this IC), which is an A/D-converter with....
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If you need a triangle wave signal or a square one but you only have a sinewave generator, use this converter to avoid the trouble of beginning from scratch. It is made up of two ICs: one LM13700 and one TL084. The amplitude of the squarewave can be varied....
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This tester is for tracing wiring on Printed Circuit Boards. Resistors below 50 ohms act as a short circuit; above 100 ohms as an open circuit. The circuit is a simple multivibrator switched on by transistor T3. The components in the base of T3 are Dl, Rl,....
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The charger in this project is designed to charge two AA NiMH or NiCd cells of any capacity (as long as they are the same) at about 470mA. It will charge 700mAh NiCds in about 1. 5 hours, 1500mAh NiMHs in about 3. 5 hours, and 2500mAh NiMHs in about 5. 5....
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It uses good stability, precision to be high outputting the direct current stream source that can be presetted often in electronic device. The numerical control direct current stream source that this text designs can well lower the output error caused....
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The purpose of this project was to be able to monitor the power consumption at my house. In addition to total usage, I wanted to be able to separately monitor & compare usage of major appliances (water heater, heat pump, furnace, etc. ). This would require....
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A circuit that can detect a light beam cut. The first circuit i made was a light/dark detector with photoresistor. Although it could sense the light cut, it had a major disadvantage: extreme interferences from ambient light. That is why i designed this....
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This project is a self-contained serial terminal using a PIC16F84 microcontroller chip, an inexpensive LCD character display, a keypad, and very little else. It is full-duplex, meaning keypresses cause RS-232 output, and RS-232 input makes characters appear....
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You may be familiar with this effect. You switch audio equipment such as an amplifier to a different input and there is a loud click or "thump" in the speaker system. Not all equipment is affected. Some high end audio systems never suffer, but intercoms....
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and the most likely problem with my wiring is ME. My apologies for the long post but I thought the more information and pictures I can provide the....
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This Frequency Counter is suitable to display the frequency of a frequency generator with an analog setting. It is a very simple counter and can be used as a module in a box with a frequency generator. It does what it says, it measures frequencies up to 2....
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A few time ago I decided to create a media center box to replace my DVD player, sattelite receiver, VCR and my kid`s Play Station 2, toone device. So, I made a core 2 duo processor system that actually replaced with succeed, all my electronic devices. The....
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A low-frequency, op-amp oscillator and a VCO, both configured from a single MC3405 ~dual op amp and dual comparator, are tbe major components in a siren circuit tbat can be made to produce various warbles and wails, or serve as an audio sweep generator. ..
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Here`s a simple lie detector that can be built in a few minutes, but can be incredibly useful when you want to know if someone is really telling you the truth. It is not as sophisticated as the ones the professionals use, but it works. It works by measuring....
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This electronic timer switch will ON your light for 100 seconds, OFF for another 100 seconds and ON again for 100 seconds after an hour of powering up the circuit. Good home project to build ..
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This is a small tv transmitter circuit wich trasmittes in VHF, negative sound modulation and PAL video modulation. It is suitable in countries where the B and G system is used. T1 which type of transformer. what is C1 value. what means of letter P which in....
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Chaolitong Phone Travel Charger for Motorola to 308,328,338 and 368 series mobile phone battery. The charger has a nickel-cadmium, nickel hydrogen, lithium-ion battery switch, ..
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As shown in the high-frequency signal generator capable of generating a low frequency 1kHz, 465kHz IF signal and the high frequency of 525 ~ 1605kHz, to repair radios or other ..
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As shown in FIG XTR108 four-wire RTD is connected to the circuit. Four-wire RTD lead resistance in practical application is usually not equal, thereby increasing a precision op..
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New uTracker on GE865 Small size. New edition of tracker (SIM300DZ, EB-230/LEA-5S). Add OBD-II (ISO) sensor, accelerometer and RFID reader. Add TR24 2.4GHz module except USB link to host. Change all to SPI (free 3 pins to buttons ?) Add u-blox LEA-5S...
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This my fist project with SMD circuit. I ignored SMD because the small sized parts are confused me. The circuit of current SMD project is the headpho....
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The battery tester uses four transistors and two LEDs to indicate the condition of any battery you want to test. Q3 and Q4 are connected in a Darlington configuration that has extremely high gain. LED L2 lights when a small positive potential appears on the....
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I`ve been getting that V_A = 15 (which is wrong). Also I think V+ is = 0 since the node below 3 ohm is grounded. Any help on how to start solving this Ok! So, what I did at first was: V+ = 0, the current 5Am is going through 3 ohm resistor => Va- 0 = 3 *5 =....
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In previous article about how to make a radio we have discussed a simple crystal radio receiver circuit. The schematic mentioned here is also a simple AM radio circuit but it is not using a crystal, it is using high gain preamplifier stage of transistor BC....
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Circuit To squeeze even more energy from a alkaline battery cell, this circuit adds two transistors to a circuit similar to the above design to boost the efficiency. A small 1. 5 volt alkaline N cell should flash the LED for a full year. It too uses a....
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Hello everyone, thank you for checking out my first Instructable. I have enjoyed seeing your creations over the years and love what all of you are con....
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The Aristo ART-5474 Accessory Panel is a complete receiver intended to control accessories through the use of the A through E buttons on the Train Engineer transmitter. As the 5474 comes, it will control two turnouts, one constant load such as lights, and....
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