Top Circuits Page 71
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This circuit can be used to operate an electric strike or an electromagnetic lock on a door. It is not the door being opened/closed, but a small electromagnetic strike which unlocks the door. The opener has the following features currently programmed in....
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CodeLock AVR electronic combination lock is realised with Atmel AVR microcontroller AT90S2313 or ATtiny2313. Program in hex code is 2 kB long. User code is consisted of 1 to 4 digits. If you buy the chip than user code is consisted of 1 to 8 digits. If the....
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To put the relay in tension the 4 buttons S1 S4 must be pressed. If anyone of the 4 butoons S5 S8 are pushed the relay donts tension ( dont receives supply voltage ).
The supply voltage must be equal to the working voltage of the relay. One transistor....
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This electronic lock can be used with any type of iButtons you may already have, since the only thing needed is the internal serial number, that's different for every iButton. The command used to read the serial number is the same for all iButtons. The....
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This circuit is very basic to build. To open a the lock which is connected to the K1 Load you must press each momentary switch in the correct sequence. The sequence used in this circuit is S1,S2,S3,S4. If any of the other switches are pressed the circuit....
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Finally I was able to control an LCD Hitachi display and a 12-key matrix keypad with only one 16F84 or 16F628. In a near future, I will be able to control a full QUERTY-type keyboard and a LCD display. The biggest improvement on this projects was the....
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his Electronic Lock circuit is not only simple but it is also very good. It can easily be configured to provide either momentary or continuous output. Key sequences of up to 9 digits are possible. You can pre-enter part of the combination and then have....
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It is a relatively simple circuit of electronic lock of safety with code of 7 digits. It should is given attention in the time that will be stepped the keys, that shape code and it does not exist it delays. With the right step of keys and if code is right....
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Only one out of 9,999 possible codes has the power to unlock this simple, yet effective, electronic lock. A combination lock is not just a perfect system to protect your belongings, it is also a valid system to let everyone to know that you are vigilant: an....
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A programmable code lock can be used for numerous applications in which access to an article/gadget is to be restricted to a limited number of persons. Here is yet another circuit of a code lock employing mainly the CMOS ICs and thumbwheel switches (TWS)....
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This simple circuit is the electronic version of the combination lock. Using the special purpose LS7220 digital lock IC, the circuit allows a 4 digit combination of your choice to activate a relay for a set period of time. This relay can then be used to....
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The Button Code is a system that allows a single button to act as a keypad. The user enters a 4 digit code into the system using button taps. The button can be placed where the public can access it since like a keypad there are many combinations to keep....
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Circuit works: Figure 5 -2a in S. Alarm switch. If you press S, after the relay K. Electrical work, two normally open contacts Pull,..
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Electronic lock using the telephone key (resistor connected plug) is inserted after the oscillator circuit start-up circuit, and the oscillation frequency is accurate or not to..
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Circuit as shown by the two and four decimal counter CD4017 password switch composed by the output terminal of the key switch logic combination of components to another feature of the electronic code switch. ..
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As shown in Figure is a circuit diagram of an enhanced lock the AE1169. AE1168 enhanced when the lock button is pressed, AE1168 through the keyboard scan to determine the corre..
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As shown in the lock circuit by a decimal counter CD4017 composed by ten its output terminal is connected through a combination of the number of passwords the group consisting ..
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Figure 1 shows the block diagram for the NTE789. The input signal form the detector is amplified by a lowdistortion
preamplifier and simultaneously applied to both signal, generated by a local voltagecontrolled oscillator
(VCO), is counted down by two....
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The circuit in Figure 1 represents an attempt to combine the best of both worlds: the simplicity of a rotary interface and the performance of a digital potentiometer...
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No description available...
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No Description available...
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The decoder`s operation is more complicated than that of the encoder. A behavioral simulation (Figure 2) shows the internal signals that are involved in the decoding process. Note that the spike on the "cd" signal is not a true spike; it appears only in the....
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The HT-12E is a CMOS IC. This encoder serially transmits data as defined by the state of the A0 to A7 and D0 to D3 input pints. On power-up, the DOUT pin is low. The HT-12E begins a 4-word transmission cycle on receipt of a transmission enable, or TE,....
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Decoding this bit stream into ASCII hex values is an ideal job for a low-cost 8-bit microcontroller. Using a microcontroller with onboard flash memory, such as the NEC Electronics µPD78F9418A (www.necelam.com), eliminates the need for external memory. The....
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The signal output by the radio control receiver is a form of PWM. This may be useful for driving servos, but is inconvenient for general electronic applications. Therefore, several of the circuits on this site convert this signal into a voltage first. This....
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This is a simple surround sound decoder. Left & right outputs of a stereo tape or CD player can be connected to the circuit inputs and 4 outputs of the circuit can be connected to a surround power amplifier or 2 stereo power amplifier. ..
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This encoder can transmit the state of up to 16 TTL digital inputs using an RF or infrared transmitter. When enabled, the included modulator automatically generates the 38kHz IR carrier. Containing a PIC microcontroller, the circuit is very flexible. You....
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The particular circuit does?t have the requirement to replace the trade decoders Surround, because this they have many more facilities and possibilities. It give however the possibility in many try with this article of decoding. The coding in Stereo Dolby....
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This design explains how to use an encoder to set the number shown by a 7-segment display. Turn the knob clockwise to increment the number, turn it counterclockwise to set it back. Encoders are the most practical (and handy) way to set a large number of....
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Decoding circuit: In order to make the various interfaces to work properly, the system needs to assign IP addresses to all ports. According to the number of system interfaces, ..
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The circuit amplifier and an attenuator control video detector consists of a composition for synchronization channel,..
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Cheap I2c shown as a bus control stereo decoder TDA9853H. Used for a digital mediation function FM radio in stereo decoding circuit after stereo encoding baseband signal by the chip feet into the first through the stereo decoder, de- tune, a voltage-controlled..
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This current to voltage converter rely on the very high input impedance of the operational amplifier. The input current (I) is forced through feedback resistor (Rf), and generates an output voltage equal to (-I x Rf). This output voltage is valid for output....
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This current to voltage converter rely on the very high input impedance of the operational amplifier. The input current (I) is forced through feedback resistor (Rf), and generates an output voltage equal to (-I x Rf)...
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AC to DC circuit is a sinusoidal alternating current into direct current crossing the circuit, if the input signal is not sinusoidal but triangular wave or sine..
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In the work process analysis circuit diagram, for example, and use of work in flyback converter transformer model. Flyback transformer is mainly composed of ideal..
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Consisting of two capacitors polarity as shown by ICL7660 and external power conversion. The power supply using a dedicated integrated circuit ICL7660 polarity inversion and ex..
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FIG humidity / frequency conversion circuit. The same as the above humidity sensors, humidity 76% isochronous The equivalent capacitance of 500pF, capacitive relative humidity variation rate was +1.7 pF /%. Circuits, A1 is the integrating circuit,..
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A current - voltage conversion circuit ..
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AD654 voltage-frequency converter is a low cost, they can work at + 5 ~ + 36V single supply, can also work in 5 18V dual supplies a maximum input voltage of 36V, the maximum op..
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Absolute shaft angle data serial-parallel conversion: the serial AD2S90 axis angle data is converted to parallel data method has many, timed digital pulse signal can be micropr..
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Application circuit works the device as shown below, a number of special occasions allowed intermittent lighting (eg doing surgery, etc.), making use of LCE module blackout eme..
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As shown by INA321/322 configured to directly drive the capacitive input A/D converter shown in Fig. Since INA321/322 output is low resistance, and therefore work at high frequ..
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As shown by INA331/332 configured to directly drive the capacitive input A/D converter shown in Fig. Since INA331/332 output is low resistance, and therefore work at high frequ..
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As shown in FIG constituted by MAX639 + 5V fixed output buck power conversion. MAX639 is a high-efficiency, step-down DC/DC converter. Input voltage range of 5.5V to 11.5V, the..
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As shown in FIG, AD7520 is a CMOS type integrated circuit DAC over 10 channel, may be provided with l0 N-bit digital output proportional to the input current Io1, it offers the..
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As shown, the circuit can get several constant current output to the load resistor RL. Since the first RL floating, rarely used. The second RL is a virtual ground, do not often..
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As shown, when the output current exceeds 40mA when, XTR110 internal 50 resistor (R9) on the need to use an external resistor REXT instead, REXT connected between 13 feet and 1..
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Circuit works as follows: The electrical circuit is a light, a light electric sound conversion circuit with two simple fiber optic connector for experimental play is shown. f W..
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This FM transmitter has a number of features, with a volume control to adjust the input level and a small, neat box to make it easier to attach to a guitar. The volume control is positioned at the end and when turned up fully, the transmitter provides fuzz....
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Take care with transmitter circuits. It is illegal in most countries to operate radio transmitters without a license. Although only low power this circuit may be tuned to operate over the range 87-108MHz with a range of 20 or 30 metres...
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A portable FM transmitter that can be used to replace a FM microphone. This simple transmitter operates from a 9V battery as shown above. I personally built this for a purpose. This is how it happened:- "members of my singing group find it difficult to....
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The design philosophy for this circuit was centered on replacing all of the op-amp circuitry found in the earlier circuits with discrete transistors and LC filters. The previous circuits had many (high quality) op-amps in series, this resulted in audible....
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Here are some utility circuits for use with the Ramsey FM10a, and other small FM stereo transmitter kits. This information may be helpful for setting up a micro powered FM radio station. The FM10a and similar kits tend to put out a low quality, broad band....
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A simple FM transmitter links your home-entertainment system to a portable radio that can be carried around the house and into the back yard. For example, you can play music on the CD changer in your living room, and listen to it on a portable radio by the....
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Here is the latest and greatly improved TX200 VFO/VCO FM transmitter. The most versatile transmitter to date that can be turned into high fidelity stereo PLL based 200mW FM transmitter. It is a perfect circuit for transmitting your music around the house and....
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Here it is a brand new TX300 FM transmitter. The amplifier has exactly the same architecture as TX500 with the difference that TX300 has only one stage variable VHF amplifier. It is a cute schematic that was made for all of you who wanted something even....
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The TX500 is a simple to build 500mW FM Transmitter. It consists of three blocks; modulator / oscillator, two stage 500mW VHF amplifier and LED based power meter. The TX500 allows to transmit audio signals to FM band at frequencies from 88 MHz to 108 MHz.....
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Here is the schematic, PC board pattern, and parts placement for a low powered FM transmitter. The range of the transmitter when running at 9V is about 300 feet. Running it from 12V increases the range to about 400 feet. This transmitter should not be used....
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The RF oscillator using the inverter N2 and 10.7Mhz ceramic filter is driving the parallel combination of N4 to N6 through N3.Since these inverters are in parallel the output impedance will be low so that it can directly drive an aerial of 1/4th wavelength.....
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This circuit is a simple two transistor (2N2222) FM transmitter. No license is required for this transmitter according to FCC regulations regarding wireless microphones. If powered by a 9 volt battery and used with an antenna no longer than 12 inches, the....
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Connect two 24 V / 3 W bulbs in parallel to the output and set the right frequency on PLL. Now turn on the transmitter. You should tune it on a receiver. Maybe you might stretch coils of the L1. Fix the L1 in position when the tuning voltage (on C4) is in....
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The transmitter includes RDS/SCA input and Audio/MPX input with optional preemphasis. It can be used with or without stereo encoder. Tuning over the FM band is provided by two buttons that control dual-speed PLL. The transmitter can work also without the LCD....
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Crystal 80mW FM transmitter circuit diagram of the production ..
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The inductor is made by winding 8 turns of #24 insulated solid copper wire on a 5 mm screwdriver. I used a conductor from a piece of category 5 quad twisted pair, left over from wiring the house with Ethernet and this seems to work well and to be easy to....
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The catering better it does not become at straight line from the network 220V but via transformer 220V/220V of isolation and safety 1A. When does not exist the R3, the force of expense is bigger, but respectively is increased also the hum 50Hz, because the....
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This transmitter needs heatsink at 2N2219. With the C4 we regulate the frequency. With their C7, C8 we adapt the resistance of aerial (practically to them we regulate so that it is heard our voice in the radio as long as you become cleaner)...
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The circuit is basically a radio frequency (RF) oscillator that operates around 100 MHz. Audio picked up and
amplified by the electret microphone is fed into the audio amplifier stage built around the first transistor. Output
from the collector is fed into....
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The circuit consists of a frequency modulated oscillator, an audio preamplifier with pre emphasis to supply the frequency modulating signal, and a buffer amplifier to drive the antenna connector. Oscillator's frequency is determined by L1 resonating with the....
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An LMX1601 Phase locked loop, a discreet FET VCO, and an AVR micro controller combine to make a stable, easy to use monophonic FM transmitter that includes a an audio activated switch that turns the transmitter on only when its being used. The common....
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This circuit uses a small microphone to capture the sound and some transistors to generate radio waves that can be picked up by a FM receiver like a car stereo. The first part is the microphone and some resistors to get it working. Next we have a capacitor....
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This is the latest BH1417 FM Transmitter design from RHOM that includes a lot of features in one small package. It comes with pre-emphasis, limiter so that the music can be transmitted at the same audio level, stereo encoder for stereo transmission, low pass....
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Here's PLL FM transmitter circuit from china. This circuit uses the familiar 2SC1971 for final power amplifier stage. The PLL controller of the FM transmitter use SAA1057 and PIC16F628 (download HEX file)...
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You'll find that this is a very easy project to build. It will transmit good quality sound in the FM band ( 88 - 108 mhz ). One inportant item is that the IC chip operates on 3 volts DC. The chip will get destroyed if it is operated on any voltage higher....
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This circuit is a simple two transistor (2N2222) FM transmitter. No license is required for this transmitter according to FCC regulations regarding wireless microphones. If powered by a 9 volt battery and used with an antenna no longer than 12 inches, the....
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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 small FM transmitter includes a limiter, a microphone amplifier and a PLL digital tuning. All the parts are placed on one circuit board. The RF power is switchable between 1 W (HI) and 0,2 W (LO). Technical specifications: Supply voltage: 12 V from....
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TR1 (BC547) is an inverted Hartley oscillator which based upon an inductor fabricated on the PCB. This makes it megga-stable, and setable anywhere in the VHF FM band (76MHz to 119MHz) and the BB105 varicap makes it voltage tuneable over about 8MHz of that....
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This will probably be one of the last transmitters for the 88MHz to 108MHz band. This particular TX is of special interest to those wishing to build low power Power Amplifiers for the VHF bands since it used impedance matching, power amplifier and antenna....
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I have had requests to add a VHF FM transmitter, to the QRP collection. This project is a simple transmitter using only one crystal and will cover 145.00 to 146.00 MHz. The crystal is a 44.9333 MHz crystal for 145.500 receive, as used in the Trio (Kenwood)....
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The power output of most of these circuits are very low because no power amplifier stages were incorporated.
The transmitter circuit described here has an extra RF power amplifier stage, after the oscillator stage, to raise the power output to 200-250....
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The RF oscillator using the inverter N2 and 10.7Mhz ceramic filter is driving the parallel combination of N4 to N6 through N3.Since these inverters are in parallel the output impedance will be low so that it can directly drive an aerial of 1/4th wavelength.....
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Here is a simple yet very useful circuit which can be used to eavesdrop on a telephone conversation. The circuit can also be used as a wireless telephone amplifier.
One important feature of this circuit is that the circuit derives its power directly from....
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FM302E-I-type FM transmitter exciter is used in Japan NECs HPB a 1210 motherboard. Direct carrier frequency modulation, phase-locked frequency stabilization and frequency synth..
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ETl3X220 is connected to a low-cost single-chip RF-transmitter chip, can provide 10 communications for wireless mouse and keyboard applications and communications products. The..
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By using only two 2n2222 transistors, this small FM band transmitter can transmit its signal to 1Km away (without obstacles between the two antennas. ..
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As shown in FIG ordinary triode 3DA87C to make long-range FM transmitter circuit,..
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I used the components on hand, comprehensive reference ..
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Circuit is shown. It consists of language and sound circuit FM transmitter circuit. Its circuit is simple and easy to manufacture. It is with an ordinary FM (FM) radio compatib..
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Circuit is shown. It consists of language and sound circuit FM transmitter circuit. The entire circuit is mounted on 25mm 35mm PCB, placing the table side, when there Jiezei bu..
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The LTC1685 is geared for half-duplex operation, whereas
the LTC1686/LTC1687 can operate in full-duplex mode. All
include a receiver fail-safe feature, whereby the receiver
output remains in a high state over the entire 12V to 7V
common mode range when....
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Recent innovations in process and circuit design have
enabled the release of three new RS485 transceivers: the
LTC®1481, LTC1483 and LTC1487. These devices share
an improved receiver circuit which features 80mA quiescent
current operation (driver....
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The LT®1785 and LT1791 RS485/RS422 transceivers
with ±60V fault tolerance solve a real-world problem of
field failures in typical RS485 interface circuits. Modems
and other computer peripherals use point-to-point RS422
connections to support higher....
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The whole Construction : You can call the transceiver like this as "OZL type". Characteristics of the "OZL type" are as follows.
1. Single conversion super.
2. Using two DBM-s as modulator and converter.
3. Modulator DBM is used as demodulator in....
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1. Full 5 watt output using a power MOSFET final that is resistant to high SWR and thermal runaway. This final is very efficient and runs much cooler than traditional bipolar designs.
2. Highly sensitive and selective superhetrodyne....
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The circuit uses easily available components. Most of the coils are wound on low cost balun core. The circuit uses ladder filter. Filter is build around four numbers of 4.43 MHz crystals. I used ladder filter because it is cheap and getting reasonably good....
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Pressing the pushbutton of the transmitter, a sound and/or light alert is activated in the receiver. The system uses no wiring or radio frequencies: the transmitted signal is conveyed into the mains supply line. It can be used at home, in any room from attic....
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The RS485 interface standard is designed to handle a 7V
to 12V input signal range; however, in practical systems,
ground potentials vary widely from node to node, often
exceeding the specified range. This can result in an
interruption of communications,....
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The circuit can be culled from the MCP2120 developer`s kit user`s guide.
It is on page 51 of document DS51246A. If you don`t want to use an integrated
transceiver, there is a circuit for you to build your own with a seperate
ir led and detector. Make sure....
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This set of two circuits from the basis for a very simple light wave transmitter. A LASER beam is modulated and then aimed at a receiver that demodulates the signal and then presents the information (voice, data, etc..). The whole thing is very easy to build....
This circuit can be used to operate an electric strike or an electromagnetic lock on a door. It is not the door being opened/closed, but a small electromagnetic strike which unlocks the door. The opener has the following features currently programmed in....
CodeLock AVR electronic combination lock is realised with Atmel AVR microcontroller AT90S2313 or ATtiny2313. Program in hex code is 2 kB long. User code is consisted of 1 to 4 digits. If you buy the chip than user code is consisted of 1 to 8 digits. If the....
To put the relay in tension the 4 buttons S1 S4 must be pressed. If anyone of the 4 butoons S5 S8 are pushed the relay donts tension ( dont receives supply voltage ). The supply voltage must be equal to the working voltage of the relay. One transistor....
This electronic lock can be used with any type of iButtons you may already have, since the only thing needed is the internal serial number, that's different for every iButton. The command used to read the serial number is the same for all iButtons. The....
This circuit is very basic to build. To open a the lock which is connected to the K1 Load you must press each momentary switch in the correct sequence. The sequence used in this circuit is S1,S2,S3,S4. If any of the other switches are pressed the circuit....
Finally I was able to control an LCD Hitachi display and a 12-key matrix keypad with only one 16F84 or 16F628. In a near future, I will be able to control a full QUERTY-type keyboard and a LCD display. The biggest improvement on this projects was the....
his Electronic Lock circuit is not only simple but it is also very good. It can easily be configured to provide either momentary or continuous output. Key sequences of up to 9 digits are possible. You can pre-enter part of the combination and then have....
It is a relatively simple circuit of electronic lock of safety with code of 7 digits. It should is given attention in the time that will be stepped the keys, that shape code and it does not exist it delays. With the right step of keys and if code is right....
Only one out of 9,999 possible codes has the power to unlock this simple, yet effective, electronic lock. A combination lock is not just a perfect system to protect your belongings, it is also a valid system to let everyone to know that you are vigilant: an....
A programmable code lock can be used for numerous applications in which access to an article/gadget is to be restricted to a limited number of persons. Here is yet another circuit of a code lock employing mainly the CMOS ICs and thumbwheel switches (TWS)....
This simple circuit is the electronic version of the combination lock. Using the special purpose LS7220 digital lock IC, the circuit allows a 4 digit combination of your choice to activate a relay for a set period of time. This relay can then be used to....
The Button Code is a system that allows a single button to act as a keypad. The user enters a 4 digit code into the system using button taps. The button can be placed where the public can access it since like a keypad there are many combinations to keep....
Circuit works: Figure 5 -2a in S. Alarm switch. If you press S, after the relay K. Electrical work, two normally open contacts Pull,..
Electronic lock using the telephone key (resistor connected plug) is inserted after the oscillator circuit start-up circuit, and the oscillation frequency is accurate or not to..
Circuit as shown by the two and four decimal counter CD4017 password switch composed by the output terminal of the key switch logic combination of components to another feature of the electronic code switch. ..
As shown in Figure is a circuit diagram of an enhanced lock the AE1169. AE1168 enhanced when the lock button is pressed, AE1168 through the keyboard scan to determine the corre..
As shown in the lock circuit by a decimal counter CD4017 composed by ten its output terminal is connected through a combination of the number of passwords the group consisting ..
This is a simple surround sound decoder. Left & right outputs of a stereo tape or CD player can be connected to the circuit inputs and 4 outputs of the circuit can be connected to a surround power amplifier or 2 stereo power amplifier. ..
This encoder can transmit the state of up to 16 TTL digital inputs using an RF or infrared transmitter. When enabled, the included modulator automatically generates the 38kHz IR carrier. Containing a PIC microcontroller, the circuit is very flexible. You....
The particular circuit does?t have the requirement to replace the trade decoders Surround, because this they have many more facilities and possibilities. It give however the possibility in many try with this article of decoding. The coding in Stereo Dolby....
This design explains how to use an encoder to set the number shown by a 7-segment display. Turn the knob clockwise to increment the number, turn it counterclockwise to set it back. Encoders are the most practical (and handy) way to set a large number of....
Decoding circuit: In order to make the various interfaces to work properly, the system needs to assign IP addresses to all ports. According to the number of system interfaces, ..
The circuit amplifier and an attenuator control video detector consists of a composition for synchronization channel,..
Cheap I2c shown as a bus control stereo decoder TDA9853H. Used for a digital mediation function FM radio in stereo decoding circuit after stereo encoding baseband signal by the chip feet into the first through the stereo decoder, de- tune, a voltage-controlled..
AC to DC circuit is a sinusoidal alternating current into direct current crossing the circuit, if the input signal is not sinusoidal but triangular wave or sine..
In the work process analysis circuit diagram, for example, and use of work in flyback converter transformer model. Flyback transformer is mainly composed of ideal..
Consisting of two capacitors polarity as shown by ICL7660 and external power conversion. The power supply using a dedicated integrated circuit ICL7660 polarity inversion and ex..
FIG humidity / frequency conversion circuit. The same as the above humidity sensors, humidity 76% isochronous The equivalent capacitance of 500pF, capacitive relative humidity variation rate was +1.7 pF /%. Circuits, A1 is the integrating circuit,..
AD654 voltage-frequency converter is a low cost, they can work at + 5 ~ + 36V single supply, can also work in 5 18V dual supplies a maximum input voltage of 36V, the maximum op..
Absolute shaft angle data serial-parallel conversion: the serial AD2S90 axis angle data is converted to parallel data method has many, timed digital pulse signal can be micropr..
Application circuit works the device as shown below, a number of special occasions allowed intermittent lighting (eg doing surgery, etc.), making use of LCE module blackout eme..
As shown by INA321/322 configured to directly drive the capacitive input A/D converter shown in Fig. Since INA321/322 output is low resistance, and therefore work at high frequ..
As shown by INA331/332 configured to directly drive the capacitive input A/D converter shown in Fig. Since INA331/332 output is low resistance, and therefore work at high frequ..
As shown in FIG constituted by MAX639 + 5V fixed output buck power conversion. MAX639 is a high-efficiency, step-down DC/DC converter. Input voltage range of 5.5V to 11.5V, the..
As shown in FIG, AD7520 is a CMOS type integrated circuit DAC over 10 channel, may be provided with l0 N-bit digital output proportional to the input current Io1, it offers the..
As shown, the circuit can get several constant current output to the load resistor RL. Since the first RL floating, rarely used. The second RL is a virtual ground, do not often..
As shown, when the output current exceeds 40mA when, XTR110 internal 50 resistor (R9) on the need to use an external resistor REXT instead, REXT connected between 13 feet and 1..
Circuit works as follows: The electrical circuit is a light, a light electric sound conversion circuit with two simple fiber optic connector for experimental play is shown. f W..
This FM transmitter has a number of features, with a volume control to adjust the input level and a small, neat box to make it easier to attach to a guitar. The volume control is positioned at the end and when turned up fully, the transmitter provides fuzz....
Take care with transmitter circuits. It is illegal in most countries to operate radio transmitters without a license. Although only low power this circuit may be tuned to operate over the range 87-108MHz with a range of 20 or 30 metres...
A portable FM transmitter that can be used to replace a FM microphone. This simple transmitter operates from a 9V battery as shown above. I personally built this for a purpose. This is how it happened:- "members of my singing group find it difficult to....
The design philosophy for this circuit was centered on replacing all of the op-amp circuitry found in the earlier circuits with discrete transistors and LC filters. The previous circuits had many (high quality) op-amps in series, this resulted in audible....
Here are some utility circuits for use with the Ramsey FM10a, and other small FM stereo transmitter kits. This information may be helpful for setting up a micro powered FM radio station. The FM10a and similar kits tend to put out a low quality, broad band....
A simple FM transmitter links your home-entertainment system to a portable radio that can be carried around the house and into the back yard. For example, you can play music on the CD changer in your living room, and listen to it on a portable radio by the....
Here is the latest and greatly improved TX200 VFO/VCO FM transmitter. The most versatile transmitter to date that can be turned into high fidelity stereo PLL based 200mW FM transmitter. It is a perfect circuit for transmitting your music around the house and....
Here it is a brand new TX300 FM transmitter. The amplifier has exactly the same architecture as TX500 with the difference that TX300 has only one stage variable VHF amplifier. It is a cute schematic that was made for all of you who wanted something even....
The TX500 is a simple to build 500mW FM Transmitter. It consists of three blocks; modulator / oscillator, two stage 500mW VHF amplifier and LED based power meter. The TX500 allows to transmit audio signals to FM band at frequencies from 88 MHz to 108 MHz.....
Here is the schematic, PC board pattern, and parts placement for a low powered FM transmitter. The range of the transmitter when running at 9V is about 300 feet. Running it from 12V increases the range to about 400 feet. This transmitter should not be used....
The RF oscillator using the inverter N2 and 10.7Mhz ceramic filter is driving the parallel combination of N4 to N6 through N3.Since these inverters are in parallel the output impedance will be low so that it can directly drive an aerial of 1/4th wavelength.....
This circuit is a simple two transistor (2N2222) FM transmitter. No license is required for this transmitter according to FCC regulations regarding wireless microphones. If powered by a 9 volt battery and used with an antenna no longer than 12 inches, the....
Connect two 24 V / 3 W bulbs in parallel to the output and set the right frequency on PLL. Now turn on the transmitter. You should tune it on a receiver. Maybe you might stretch coils of the L1. Fix the L1 in position when the tuning voltage (on C4) is in....
The transmitter includes RDS/SCA input and Audio/MPX input with optional preemphasis. It can be used with or without stereo encoder. Tuning over the FM band is provided by two buttons that control dual-speed PLL. The transmitter can work also without the LCD....
Crystal 80mW FM transmitter circuit diagram of the production ..
The inductor is made by winding 8 turns of #24 insulated solid copper wire on a 5 mm screwdriver. I used a conductor from a piece of category 5 quad twisted pair, left over from wiring the house with Ethernet and this seems to work well and to be easy to....
The catering better it does not become at straight line from the network 220V but via transformer 220V/220V of isolation and safety 1A. When does not exist the R3, the force of expense is bigger, but respectively is increased also the hum 50Hz, because the....
This transmitter needs heatsink at 2N2219. With the C4 we regulate the frequency. With their C7, C8 we adapt the resistance of aerial (practically to them we regulate so that it is heard our voice in the radio as long as you become cleaner)...
The circuit is basically a radio frequency (RF) oscillator that operates around 100 MHz. Audio picked up and amplified by the electret microphone is fed into the audio amplifier stage built around the first transistor. Output from the collector is fed into....
The circuit consists of a frequency modulated oscillator, an audio preamplifier with pre emphasis to supply the frequency modulating signal, and a buffer amplifier to drive the antenna connector. Oscillator's frequency is determined by L1 resonating with the....
An LMX1601 Phase locked loop, a discreet FET VCO, and an AVR micro controller combine to make a stable, easy to use monophonic FM transmitter that includes a an audio activated switch that turns the transmitter on only when its being used. The common....
This circuit uses a small microphone to capture the sound and some transistors to generate radio waves that can be picked up by a FM receiver like a car stereo. The first part is the microphone and some resistors to get it working. Next we have a capacitor....
This is the latest BH1417 FM Transmitter design from RHOM that includes a lot of features in one small package. It comes with pre-emphasis, limiter so that the music can be transmitted at the same audio level, stereo encoder for stereo transmission, low pass....
Here's PLL FM transmitter circuit from china. This circuit uses the familiar 2SC1971 for final power amplifier stage. The PLL controller of the FM transmitter use SAA1057 and PIC16F628 (download HEX file)...
You'll find that this is a very easy project to build. It will transmit good quality sound in the FM band ( 88 - 108 mhz ). One inportant item is that the IC chip operates on 3 volts DC. The chip will get destroyed if it is operated on any voltage higher....
This circuit is a simple two transistor (2N2222) FM transmitter. No license is required for this transmitter according to FCC regulations regarding wireless microphones. If powered by a 9 volt battery and used with an antenna no longer than 12 inches, the....
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.....
This small FM transmitter includes a limiter, a microphone amplifier and a PLL digital tuning. All the parts are placed on one circuit board. The RF power is switchable between 1 W (HI) and 0,2 W (LO). Technical specifications: Supply voltage: 12 V from....
TR1 (BC547) is an inverted Hartley oscillator which based upon an inductor fabricated on the PCB. This makes it megga-stable, and setable anywhere in the VHF FM band (76MHz to 119MHz) and the BB105 varicap makes it voltage tuneable over about 8MHz of that....
This will probably be one of the last transmitters for the 88MHz to 108MHz band. This particular TX is of special interest to those wishing to build low power Power Amplifiers for the VHF bands since it used impedance matching, power amplifier and antenna....
I have had requests to add a VHF FM transmitter, to the QRP collection. This project is a simple transmitter using only one crystal and will cover 145.00 to 146.00 MHz. The crystal is a 44.9333 MHz crystal for 145.500 receive, as used in the Trio (Kenwood)....
The power output of most of these circuits are very low because no power amplifier stages were incorporated. The transmitter circuit described here has an extra RF power amplifier stage, after the oscillator stage, to raise the power output to 200-250....
The RF oscillator using the inverter N2 and 10.7Mhz ceramic filter is driving the parallel combination of N4 to N6 through N3.Since these inverters are in parallel the output impedance will be low so that it can directly drive an aerial of 1/4th wavelength.....
Here is a simple yet very useful circuit which can be used to eavesdrop on a telephone conversation. The circuit can also be used as a wireless telephone amplifier. One important feature of this circuit is that the circuit derives its power directly from....
FM302E-I-type FM transmitter exciter is used in Japan NECs HPB a 1210 motherboard. Direct carrier frequency modulation, phase-locked frequency stabilization and frequency synth..
ETl3X220 is connected to a low-cost single-chip RF-transmitter chip, can provide 10 communications for wireless mouse and keyboard applications and communications products. The..
By using only two 2n2222 transistors, this small FM band transmitter can transmit its signal to 1Km away (without obstacles between the two antennas. ..
As shown in FIG ordinary triode 3DA87C to make long-range FM transmitter circuit,..
I used the components on hand, comprehensive reference ..
Circuit is shown. It consists of language and sound circuit FM transmitter circuit. Its circuit is simple and easy to manufacture. It is with an ordinary FM (FM) radio compatib..
Circuit is shown. It consists of language and sound circuit FM transmitter circuit. The entire circuit is mounted on 25mm 35mm PCB, placing the table side, when there Jiezei bu..
The whole Construction : You can call the transceiver like this as "OZL type". Characteristics of the "OZL type" are as follows. 1. Single conversion super. 2. Using two DBM-s as modulator and converter. 3. Modulator DBM is used as demodulator in....
1. Full 5 watt output using a power MOSFET final that is resistant to high SWR and thermal runaway. This final is very efficient and runs much cooler than traditional bipolar designs. 2. Highly sensitive and selective superhetrodyne....
Pressing the pushbutton of the transmitter, a sound and/or light alert is activated in the receiver. The system uses no wiring or radio frequencies: the transmitted signal is conveyed into the mains supply line. It can be used at home, in any room from attic....
This set of two circuits from the basis for a very simple light wave transmitter. A LASER beam is modulated and then aimed at a receiver that demodulates the signal and then presents the information (voice, data, etc..). The whole thing is very easy to build....