Circuit Diagram

Practical multi-function timer circuit

Published:2011/5/17 21:48:00 Author:TaoXi | Keyword: Practical, multi-function, timer

Practical multi-function timer circuit   (View)

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KBC-Ⅱ programmable power supply circuit diagram

Published:2011/5/12 22:29:00 Author:Rebekka | Keyword: programmable power supply

KBC-Ⅱ programmable power supply circuit is composed of the D/A converter, voltage reference, voltage comparators, operational amplifiers Al ~ A3, the output voltage adjustable regulator, CPU, monitor and keyboard. The order and the sizeof the output voltage is set by the keyboard and achieved by computer control. The principle circuit diagram of the programmable power supply is shown as above.   (View)

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555 four words cycle neon light light control circuit

Published:2011/5/22 19:09:00 Author:TaoXi | Keyword: four words cycle, neon light, light control

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 IC2(555) and R2，R3，RP1，C3.etc. It's frequency depends on RC's charging and discharging time constant, f=1.44/(R2+2R3+RP1)C3. The parameters of the figure's oscillation frequency is about 0.1～2.2Hz, the corresponding oscillation period is 10～0.46 seconds. By adjusting RP1, you can change the oscillation period.   (View)

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555 light control automatic flashing road-sign light circuit

Published:2011/5/22 7:32:00 Author:TaoXi | Keyword: light control, automatic flashing, road-sign light

As the figure 17-44 shows, the circuit is composed of the transformer rectifier circuit, the light control switch and the 555 astable multivibrator.etc. The VT tube is the 3DU-type phototransistor, when there is the illumination, the port voltage of this transistor is less than 1.6V, the power switching tube TWH8778 cuts off because the control voltage of pin-5 is low, 555 has no power supply voltage. At night, the photodiode resistance increases, the circuit opens, the TWH8778 control port pin-5's voltage is higher than 1.6V, 555 get power to work, the oscillation frequency f=1/1.44(R2+R3)C2.   (View)

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555 new high frequency fluorescent lamp circuit

Published:2011/5/22 19:42:00 Author:TaoXi | Keyword: new, high frequency, fluorescent lamp

As the figure 17-21 shows, the high-frequency fluorescent lamp circuit is composed of the step-down rectifier circuit, the high-frequency oscillator circuit and the power driving stage.etc. This kind of light has no scintillation effect of the common fluorescent lamp (Working frequency is 50Hz), so it saves the ballast and starter. The AC step-down circuit and the bridge type rectifier circuit supply the power supply voltage of VDD=+15V to the 555. The astable multivibrator is composed of the IC1(555) and RP1，D7，C5, f=1.44/RP1C5, the parameters of the figure has the oscillation frequency of 50kHz. IC1's output square wave drives the FET power transistor 2SK320.   (View)

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555 automatic exposure timer circuit (1)

Published:2011/5/22 20:06:00 Author:TaoXi | Keyword: automatic exposure, timer

As the figure 17-6 shows, the circuit is composed of the step-down rectifier circuit and the 555 monostable circuit. The monostable circuit is composed of the 555 and photoconductive resistance RG, C2, when you press the button AN, 555 circuit sets, pin03 has the high electrical level to trigger the SCR, the expose lamp turns on. When the photoconductive resistance has no illumination, the resistance is so big, when the light turns on, the resistance of the photoconductive resistance reduces, the power supply charges C2 through the photoconductive resistance, when pin-6's voltage is higher than 2/3VDD, pin-3 has the low electrical level, SCR cuts off, the light turns off.   (View)

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555 nighttime automatic bright showing light circuit

Published:2011/5/23 1:58:00 Author:TaoXi | Keyword: nighttime, automatic, bright showing, light circuit

As the figure 17-37 shows, this circuit is composed of a photoelectric switch and a oscillator, it can be used to automatically show the signs and barriers. The phototransistor VT1(3DU5) has the low resistance because of the illumination, VT2 cuts off, VT3 conducts, SCR cuts off because of the G port has the low electrical level, the indicating light turns off. At night, the c-e of the 3DU5 tube has the high resistance, VT2 conducts, VT3 cuts off, SCR conducts, and the IC starts working. The astable multivibrator is composed of the IC and RP1，R5，R6，C1, T=0.693(RP1+R5+R6)C1, the oscillation period is in the range of 2 to 10 seconds.   (View)

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555 rock color light controller circuit

Published:2011/5/23 2:13:00 Author:TaoXi | Keyword: rock, color light, controller

As the figure 17-56 shows, the controller is composed of the step-down rectifier circuit, the 555 multivibrator, the color light control circuit, and it can be used to parallelly control the 220V，5W small power color lights or series rock control the 6-12V small light bulbs. The astable multivibrator is composed of the 555 and D3，D4，RP1，C2, by adjusting RP1, you can change the circuit's charging and discharging time constant to make the duty cycle of the alternating square wave to 2:1. When pin-3 outputs the low electrical level, the discharge tube of the substrate discharges, the pin-7 has the low electrical level, LED1 turns on, J1 closes, the first group of color lights turn on. Then this circuit goes round and round.   (View)

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555 camera flash delay circuit

Published:2011/5/23 2:46:00 Author:TaoXi | Keyword: camera, flash, delay circuit

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 shadowed, the positive transition pulse adds to the VT2. The IC1(555) is triggered by the low-level pulse, 555 sets, pin-3 has the low electrical level, VT3 conducts, SCR conducts too. The monostable timing circuit is composed of the IC1 and RP2，R4，C2, the temporary stabilization time td=1.1(RP2+R4)C2.   (View)

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555 fluorescent group centralized rectification and start-up circuit

Published:2011/5/23 2:30:00 Author:TaoXi | Keyword: fluorescent group, centralized rectification, start-up circuit

This centralized rectification and start-up circuit can drive 10-20 cigarettes of fluorescent lights to work. It is composed of the step-down rectifier circuit, the passive stimulating type high-frequency push-pull oscilation circuit and the driving circuit, as the figure 17-64 shows. The multivibrator is composed of the time base 555 and the R2，R3，C3, the oscillation frequency f=1.44(R2+2R3)C3. The parameters of the figure's oscillation frequency is about 25kHz. The high-frequency pulse which is output by 555 adds to the primary stage of pulse transformer T1, the push-pull driving circuit is composed of the two secondary stages and the VT1，VT2，R4～R7.etc.   (View)

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The power test circuit

Published:2011/5/22 0:50:00 Author:Borg | Keyword: power test

The figure is a power test circuit. Power is equal to voltage multiplies current. The circuit is formed by a multiplier of μPCl32. The input voltage is imposed on the 10 pin interface through RP1(electricity distributor), and the input current is imposed on the 9-pin of μPCl32 after being magnified. The power is delivered out by A2 after the input current multiplies the input voltage. By the way, the max voltage on the 9 and 10 pins can be higher than ±lOV, which could be set by the resistances of RP1 and RP2.When adjusting, connect the 10-pin of the voltage input terminal with the ground at first.   (View)

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The liquid concentration measuring circuit

Published:2011/5/22 1:08:00 Author:Borg | Keyword: liquid concentration, measuring circuit

This is a liquid concentration measuring circuit. The principle of the circuit is that to insert two poles in the liquid, and get the voltage, then the concentration of the liquid is indicated by the meter. The AC voltage is reduced by the transistor of T1, and then is change into a square wave potential after passing VDZ1 and VDZ2, the stabilizers. Thus, the AC voltage is hold by the stabilizer tube, and the change of power supply wouldn't affect the measured circuit. The square wave potential is imposed on the base electrode of VT1 by the pole, and it changes with the concentration of the liquid.   (View)

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The temperature test circuit of thermistors

Published:2011/5/19 23:59:00 Author:Borg | Keyword: test circuit, thermistors

The figure is a temperature test circuit with thermistors. In the circuit, thermistors are used as the temperature sensor RT, the testing temperature is divided into 9 levels. By using comparators of Al一A8, the output high-low LEV represents the tested temperature. The relationships between LEV output by U.I-U.8 and temperature are listed in the table.   (View)

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Thermostat for Medical (the 3rd)

Published:2011/5/22 9:36:00 Author:Felicity | Keyword: Thermostat for Medical (the 3rd)

Work of the circuit The circuit consists of power circuit, infrared controlling circuit, temperature examining circuit and temperature unusual warning circuit (It is showed in picture 9-42.). When the temperature is lower than the reset temperature the semiconductor refrigerator starts to work and heat. And when the reset temperature is reached it stops working. In this way the temperature of the thermostat is kept in a reset range. When the temperature is higher than the reset temperature the semiconductor refrigerator starts to work and refrigerate. And when the reset temperature is reached it stops working. In this way the temperature of the thermostat is kept in a reset range.   (View)

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Thermostat for Medical (the 2nd)

Published:2011/5/22 9:35:00 Author:Felicity | Keyword: Thermostat for Medical (the 2nd)

Work of the circuit The circuit consists of power circuit, temperature examining circuit and controlling executing circuit (It is showed in picture 9-41.). When we use it to heat we should put S2 in the site “heating”. If the temperature is higher than the reset temperature the heating circuit does not work. If the temperature is lower than the reset one the heating circuit works. When we use it to refrigerate we should put it in the site “refrigeration”. If the temperature is higher than the reset temperature the refrigerating circuit works. If the temperature is lower than the reset one the refrigerating circuit does not work.   (View)

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555 practical DC stepless light modulator circuit

Published:2011/5/22 19:16:00 Author:TaoXi | Keyword: practical, DC, stepless, light modulator

As the figure 17-41 shows, the light modulator uses 555 as the core. The astable multivibrator is composed of the 555 and R1，RP，R2，C1, the oscillation frequency f=1.44/(R1+RP+R2)C1, it is about 650Hz. The duty cycle range is from 4.5% to 95.5%, you can change the duty cycle by adjusting RP, so the brightness of light changes in a wide range, we realize the free dimming.   (View)

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555 small electronic jewelry circuit

Published:2011/5/22 19:31:00 Author:TaoXi | Keyword: small electronic jewelry

As the figure 17-50 shows, the small electronic jewelry is composed of the 555 and the luminotron. The astable multivibrator is composed of the 555 and R1，R2，C1, the oscillation frequency f=1.44/(R1+2R2)C1, it is about 2Hz (it flashes twice per second). If the LED1～LED4 use different colors of LEDs, the effect is more better. R3，R4 are the current limiting resistor.   (View)

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555 automatic exposure timer circuit (2)

Published:2011/5/22 20:13:00 Author:TaoXi | Keyword: automatic exposure, timer circuit

As the figure 17-7 shows, the monostable delay circuit is composed of the 555 and C1, cadmium sulfide photoresistor RG.etc. You install the RG near the photo, when exposure, if you press AN, 555 sets, J closes, the exposure light (white) turns on. If the illumination is strong, RG has the low resistance, td=1.1RGC1; if the illumination is weak, RG has the high resistance, td will be long. When the time of td is up, J releases, the white light turns off, the red light turns on, the exposure time complete. Figure 17-7 The 555 automatic exposure timer circuit (2)   (View)

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555 music color light controller circuit

Published:2011/5/22 20:27:00 Author:TaoXi | Keyword: music, color light, controller

As the figure 17-52 shows, the controller is composed of the acousto-electric conversion circuit, the amplifier circuit, the clock pulse generator, the counter circuit and the control circuit. It controls the 4 channels of color lights to flash with the music. The pickup microphone changes the music sound into the electric signal, and this signal adds to the 4 channels of analog switch IC3(CD4066). The astable multivibrator is composed of the 555 and RP1，R1，R2，D1，C1. The parameters' oscillation period T is between 0.5～5 seconds. Pin-3's output of the 555 adds to IC2 as the CP pulse. IC2 uses the CMOS type decimal counter/pulse divider CD4017.   (View)

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555 emergency DC fluorescent lamp circuit

Published:2011/5/22 20:40:00 Author:TaoXi | Keyword: emergency, DC, fluorescent lamp

As the figure 17-19 shows, the astable multivibrator is composed of the 555 and R1，R2，C2, the oscillation frequency f=1.44/(R1+2R2)C2. The parameters of the figure have the high frequency oscillation frequency of 70kHz. The high-frequency square wave signal from the pin-3 is limited, then it adds to the VT tube, after the process of boost, this signal drives the light to turn on. The transformer iron core uses the GU30X20 ferrite tank shape iron core.   (View)

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