Repository-circuits
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A basic circuit of the transistor UHF radio transmitter with surface acoustic wave resonator (SAW), and the SAW is used as a positive feedback element connected between the transistor VT base and LC network in parallel. Figure (b) shows another basic....
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IT usesDTMF encoder output dual tone multi-frequency coded signal to modulate the transmitted carrier frequency. It can form a DTMF encoded radio paging system. The circuit uses DTMF encoding UM97085 and decoding circuit YN9101 circuit to form a small....
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The telecontrol receiving decoding circuit`s performance index shown as the chart are as follow: f radio frequency =27MHz, f audio frequency =5.5KHz, 100% modulation - square-wave; f radio frequency=±600Hz, and the frequency shift keying (FSK) is 160Hz, and....
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This device adopts encoding and decoding circuit MC145026/ MC145027 and RF transmitter / receiver module TDA1808/ TDA1809, and it can beflexibly operated inthe range of 10~120m, and people have no need to change orginal mouse eterior apperance and inside....
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A, B are 2 common contact, outline drawing and pin definition. C is the infrared emission tube shape, pin definition and schematic symbol. CD4069 is the pin definition of inverter pin, and F is the 9013 transistor shape, pin definitions and symbol....
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The circuit monitors PC keyboard activity through five-pin DIN connector J1. When the user presses a key, the keyboard sends a series of negative-going pulses on pin 2. In conjunction with Q1 and C3, the op amp essentially functions as an integrator, which....
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PCA84C-440/441 is the single-chip microcomputer integrated circuit produced by Philips company, it is widely used in domestic and imported large screen color TV, such as Philips and other color television.1. The internal block circuit diagram and pin....
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PIC16C57-RCT is communication single-chip microcomputer integrated circuit, which is widely used in Qiao Xing series of IC card management telephone. 1. Function descriptionPIC16C57-RC integrated circuit includes pulse and dual-tone dialing circuit, memory....
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This circuitry is used for the joggle between computer Z RS-23 serial connecting current ring and current ring circuitry, it can transform the voltage semaphore of transmission into the current semaphore with 20 mA, the biggest speed can reach 1200 bits.....
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This is a circuit intended to be used in basketball shot clock.Notes:To start in 24 seconds; 24s LOAD SW and Reset SW should be push simultaneously. If not, the count will start in 99. Pulse input can be connected to 555 astable multivibrator but must be....
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The 27MHz crystal oscillator circuit is as shown in the figure. The R1, R2, R3 are the biasing resistor, the C6 is the bypass capacitor, the voltage division circuit is composed of the C1, C3, C4 and C2 to control the oscillation strength. The L1 is the....
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Each part of LCD has individual counter, latch, decoder and driver. Pumping signal feeds back to the motherboard of LCD. When the display section is disconnected, the phase and amplitude of the motherboard and display segment drive signal are the same. It....
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As the figure 15-24 shows, the controller circuit is composed of the switch type Hall integrated circuit DN838 and the astable multivibrator (composed of the 555), this circuit can be used in wide range of applications such as the automatic door opening,....
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As the figure 17-1 showns, the camera flash delay circuit can be used to capture the high-speed scene, and you can get a very short exposure time. The light door is composed of the luminous diode and the 3DU type photosensitive tube. When the light is....
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This control circuit is composed of the AC step-down rectifier circuit, the astable multivibrator, the timing control circuit, the optocoupler circuit and the SCR driving circuit.etc. As the figure 17-61 shows. The astable multivibrator is composed of the....
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As the figure 15-22 shows, the doorbell is composed of the monostable timing circuit, the password switch, the NAND gate circuit and the sound circuit.etc. In the limited time, the circuit uses the program to press the password switch, the doorbell circuit....
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This circuit provides a visual 9 second delay using a 7 segment digital readout LED. When the switch is closed, the CD4010 up/down counter is preset to 9 and the 555 timer is disabled with the output held high. When the switch is opened, the timer produces....
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Made of SS0001 human pyroelectric voice alarm circuit diagram as shown: Pyroelectric infrared language warning device described in this article can be used to prevent electric shock or theft, after a little modification can also be used for automatic light....
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We can use the flash beam to supply the remote control for the AC power devices. The important point of this device is the memory function. It can continuously supply the power to the device. When it acts the second time, the power will be cut off....
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The locker alarm circuit or cashbox watcher can be used to protect a cashbox/locker from unauthorised access. This tried and tested design forms a fool-proof,remotely operated alarm/electromagnetic relay driver that receives its control signal from a....
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Gates U1-a and U1-b of the 4093 quad 2-tnput NAND Schmitt trigger are connected in variable, low-frequency, square-wave oscillator circuits. The output of gate U1-a is connected to one of the inputs of gate U1-b. The square-wave output of gate U1-a modulates....
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This circuit offers open and closed loop contacts (switches 1,2,3) that triggers the alarm ON and stays ON for 5 -10 minutes. The trigering delay (entrance/exit) is 27 seconds. This simple alarm circuit Has also a cancel button for reseting the circuit to....
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Human infrared thermal release alarm can receive the heat releasing infrared ray issued by the body during the day or night, then it willgive the sound and light alarm. It is ideal for electronic guard. Working principle: The circuit uses imported IC,....
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Infrared burglar alarm circuit schematic is shown in Figure 1. Infrared transmitter is a multivibrator with oscillation frequency being 40kHz, and it is composed of IC2 ( NE555 ), R1, R2 and C3. VLS is the infrared emission probe which can be used to radiate....
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In the event of combustible gas, the conductance of TGS308 gas sensor increases, and the voltage is removed through the potentiometer RP1 slide point, and its value is increased from normal 3V rms to 20V. This elevated voltage is added to transistor VT1....
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This small water sensor alarm circuit makes a loud warning sound when a humidity sensor detects a quantity of water. This circuit assembly is an application of low power comparator LM1801 made by National Semiconductor. The reference voltage for the....
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Starting from today I will try to post interesting Arduino projects from around the web. I am novice in this domain but I am giving my best to fully understant it. I must say from the begining that the projects are not developed by me and I will link the....
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Figure shows the bean sprouts automatic watering control circuit. The controller consists of step-down rectifier circuit, power outage told implement (IC3), timing control circuit (IC1), temperature control circuit(IC2) and so on. The step-down rectifier....
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The circuit is shown as the chart. It is a control circuit which composed of infrared specific integrated circuit KC778B and KC778B is the center of the circuit. It s surrounded by a pyroelectric infrared sensor head PIR, light control and light control....