Signal Processing

555 simple sickbed calling device circuit

Published:2011/5/25 1:35:00 Author:TaoXi | Keyword: simple sickbed, calling device

As the figure 16-8 shows, the controllable multivibrator is composed of the 555 and R1，R2，C1, the circuit start-up depends on the electric potential of the reset port pin-4. Whenyou press any one swith of the K1～K4, pin-4 has the high electric potential, 555 starts working to send out the sound and light alarm signals. The oscillation frequency f=1.44/(R1+2R2)C1, it is about 1000Hz.   (View)

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555 simple acupuncture point detector circuit

Published:2011/5/29 19:50:00 Author:TaoXi | Keyword: 555, simple, acupuncture point, detector

As the figure 16-19 shows, the acupuncture point detector is composed of the acupuncture point detector circuit and the trigger displaying circuit. One detection probe of the acupuncture point detector is in the hands of the measured person, another detection probe connects to the skin of the measured person, when the probe is closing or touching the acupuncture point, the resistance between the two electrodes is low, so the composited tubes VT1 and VT2are in the saturated conductivity state, the pin-2 of 555 has low electrical level, IC sets, VT3 conducts and sends out the sound and light reminding signals, this means the point detection is right; at the position of non-acupuncture point, the skin resistance is high, VT1 and VT2 cut off, 555 is in the resetting state, there is no light siganl.   (View)

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555 male and female voice electronic guest greeting circuit

Published:2011/6/2 1:02:00 Author:TaoXi | Keyword: 555, male, female, voice, electronic, guest greeting

The monostable delay circuit is composed of the IC1(555) and the R1，C1. When you areopening the door, the door control switch MK makes the pin-2 of 555 to connect with the ground, the 555 sets, the J closes, and J1-1 connects with the C4, the door control switch makes the pin-3 and pin4 of IC2 in the short-circuit state, and also the door control switch triggers the pin-3 and pin-4, so the circuit sends out the high pitch female voice thank you for coming , then the temporary stability time of the monostable circuit is up, J releases to connect the J1-1 to the C5, the circuit sends out the high pitch male voice thank you for coming . When you design the circuit parameters, the press time of the door control switch is about 3-4s, the time of broadcasting a word is about 1.4s, so we choose the monostable temporary stability time 1.4s   (View)

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The protection circuit of 555 fridge(2)

Published:2011/5/26 23:21:00 Author:Borg | Keyword: protection circuit

See as Figure 13-7, the circuit includes step-down rectified circuit, turning on delay circuit and controllable silicon control circuit. In the circuit, the connection of C4 and R4 can help with power failure protection. Because when it starts to electrify, the voltage on C4 can not be changed suddenly, which makes 555 reset, and the 3-pin is in a low LEV, SCR is blocked and the outlet is out of power. When C4 charges the negative pole of the capacitor, i.e the 2-pin is 1/3VDD lower than the trigger LEV, 555 is set, 3-pin is in a high LEV, SCR is conducting, and the outlet gets power. The delayed time of starting is td=1.1R4C4, and the delayed time of parameters indicated in the figure is about 6 min.   (View)

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The control circuit of 555 multiple fridge

Published:2011/6/7 4:27:00 Author:Borg | Keyword: control circuit

See as Figure 13-11, the control circuit includes sub-circuits of over voltage sampling, low voltage sampling, time delay starter,sound & light alarm device and step-down rectifier, etc. Its main functions are auto protection of over voltage, low voltage and over current, delaying starting of instant power-off, light&sound alarm for faults and so on. IC1(555),C6,R14,RP3 and so on form a time delay starting circuit, when the fridge is power-on, or it is power-off then the power is on again, as the voltage on C6 can not mute, only when RP3 and R14 charge C6 and the LEV of C6 is lower than the 2-lead trigger LEV of 1/3VDD does 555 reset and J pull in.   (View)

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The 555 double-cylinder washing machine timer and washing mode selector circuit

Published:2011/6/7 4:30:00 Author:Borg | Keyword: double-cylinder, washing machine, washing mode

See as Figure 13-17, this circuit can replace machine timers, which can fulfill washing and dehydrating. It is equipped with functions of washing timing for 5,10 and 15min; dehydrating for 1,3 and 5 min; washing modes of power washing, general washing and slight washing. Figure 13-17 the double-cylinder washing machine timer and washing mode selector circuitIC1,R1~R3 and C1 form the dehydration timing circuit, the time span is selected by K1; IC1,R1~R5 and C1 consists the washing timing circuit, the time span is chosen by K2. K4 is the washing/dehydrating switch.   (View)

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The protection outlet circuit of 555 small-sized fridge

Published:2011/6/7 4:31:00 Author:Borg | Keyword: protection outlet circuit, small-sized fridge

The circuit is based on 555, which has the virtues of small size, low cost and reliable time delay. The circuit consists of step-down rectifier circuit, time delay circuit and relay controller circuit, etc, which is as shown in Figure 13-21. The step-down rectifier circuit consists of step-down capacitor C1,C2 and full bridge circuit QD, C2 and so on , the rectified voltage is stabilized by R2 and DW and then becomes a DC voltage of +9V, finally, it becomes the working voltage of the next circuit.555,C4 ,R3 and so on consist a single steady time delay circuit. Figure 13-21 The protection outlet circuit ofthe small-sized fridge   (View)

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The simple natural wind analog circuit

Published:2011/6/7 4:33:00 Author:Borg | Keyword: natural wind, analog circuit

See as Figure 12-4, the circuit includes a step-down rectifier current and a 555-based non-steady multi-resonate oscillator. The voltage after being rectified is VDD≈12V. 555,R1,RP1,D2,D3 and C3 consist a non-steady multi-resonate oscillator. By adjusting RP1, we can change the duty cycle of the output wave. The output period square wave controls the conduction and end of SCR by the current limited resistance R2, so the power supply of the fan gets power now and then, but it keeps rotating due to the inertia, and the result is like the natural wind.   (View)

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The 555 analog natural wind control circuit of Meifeng fan

Published:2011/6/1 3:25:00 Author:Borg | Keyword: natural wind, control circuit

The circuit is shown in Figure 12-34, which consist of sub-circuits of AC step-down rectifier, low-frequency non-steady multi-resonate oscillator and relay controller motor, etc. This circuit is simple. And the simulated wind is vivid, it is strong sometimes or weak other times, so the effect is good.The time-based 555 circuit, R1,R2,RP1,RP2,C3 and so on consist a non-steady multi-resonate oscillator, the oscillating frequency is very low, which is T=0.693(R1+RP1+R2+RP2)C3 The oscillating period of the parameter in the figure ranges 13~44s, which can be regulated by adjusting RP1 and rp2.   (View)

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The 555 electronic ventriloquism circuit

Published:2011/5/27 2:49:00 Author:nelly | Keyword: electron, ventriloquism, sound circuit

As shown on the figure 11-18, this circuit consists of three 555 circuits and a field effect transistor. IC1, IC2 and IC3 all work in the state that is unsteady and multi-vibration, the difference is that IC2's discharge end 7 foot contacts the field effect transistor VT1's source. When the C7's voltage on the IC3 oscillation circuit changes, the VT1's grid voltage also changes. This electrical resistance D-S changes with the voltage G-S, which leads IC2 to produce the variable oscillation frequency, the frequency is between 1Hz and 300Hz. It can simulate many kinds of sounds through the integrated test among the potential including RP1, RP2, RP3, RP4.   (View)

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The 555 touching nose game circuit

Published:2011/5/27 2:48:00 Author:nelly | Keyword: 555, touching nose, circuit

The Monostable trigger circuit consists of the 555, R1 and C1. The circuit doesn't be triggered ordinarily and its three foot is low level. When the body touchs the biyu , the 555 will flip, and then get into the triplet state. The temporary stability time : td=1.1R1C1, the corresponding pulse width to the figure is about 10s. In the triplet state, the high level which is output by the three foot combines with the IC2 and plays music. Every music IC all can use it, but we must notice the voltage.   (View)

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The relationship circuit diagram betweent frequency band and capacitance capacity

Published:2011/6/9 22:38:00 Author:Sophia | Keyword: Frequency band, Capacitance capacity

The diagram shows that the capacitance should be adopted with different capacitance, the capacitor should adopt ceramic capacitor with excellent frequency characteristic.   (View)

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555 big white mouse training

Published:2011/5/24 2:53:00 Author:TaoXi | Keyword: big white mouse, training, lost box

The lost box is composed of three radiant arms, on the top of each arm there is a signal light, the zone which has the light signal is the safety zone. In the experiment, we require each arm should have three functions. The lost box circuit is composed of the step-down voltage stabilization circuit, the constant-current source circuit, the timing sequence control circuit and the three-channel trigger control circuit.etc. The multivibrator is composed of the IC4(555) and 4R1，4R2,4C1, it is used as the timing sequence control circuit, the oscillation period T=0.693(R1+2R2)C1, the tcharging=0.693(R1+R2)C1, it is about 30 seconds, so the high level output time is 30 seconds; tdischarging=0.693R2C1, it is about 15 seconds.   (View)

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555 ozone tube electronic disinfection circuit

Published:2011/5/23 8:22:00 Author:TaoXi | Keyword: ozone tube, electronic disinfection

The figure 16-39 shows the ozone generator circuit with the ozone tube, it is composed of the multivibrator, the boost driver stage and the ozone tube. The multivibrator is composed of the time base circuit 555 and the R1，R2，C3, it's oscillation frequency is preferably between the 15-20kHz, the oscillation frequency in the figure depends on the R1, R2 and C3's charging and discharging time constant, fc=1.44/(R1+2R2)C3. The parameter of the figure is 18kHz. The 555 output oscillation square wave makes the indicator light to shine, at the same time this square wave adds to the b pole of the VT1 power transistor through the current limiting resistor R4, and then it is amplified by VT1 to drive the transformer T. The ozone tube uses the 8mm X 63mm H63815 type tube, the terminal voltage is about 1500V, the working current is about 2.3mm,and the service life is not less than 1500 hours.   (View)

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555 stimulated ozone generator circuit

Published:2011/5/23 8:53:00 Author:TaoXi | Keyword: stimulated, ozone generator

This ozone generator is composed of the step-down rectifier circuit, the multivibrator source and the ozone generating piece. The circuit is as shown in figure 16-37. The power supply is composed of the step-down transformer and the full-bridge rectifier circuit, after the voltage stabilization of the 7809, the power supply supplies the +9V DC voltage. The multivibrator is composed of the time base circuit 555 and the R3，R4，C4, the oscillation frequency is f=1.44/(R3+2R4)C4. The figure parameter's oscillation frequency is about 30 kHz. The 555 output pulse sequence (the duty ratio is about 1:1) drives the high-frequency pulse transformer T1 through the power tube VT1, the bubprime output voltage is about 3000V. This kind of high-frequency high-voltage pulse adds to the ozone generating pottery to produce the ozone by the corona discharging principle.   (View)

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555 multi-purpose electronic treatment health device circuit

Published:2011/5/23 22:18:00 Author:TaoXi | Keyword: multi-purpose, electronic, treatment, health device

As the figure 16-21 shows, the low-frequency multivibrator is composed of the IC1 and R1，RP1，C1, f=1.44/(R1+RP1)C1, the oscillation frequency is in the range of 0.5～187Hz. If K1 is in the different positions, IC1 can output the square wave, sawtooth wave and the delta wave. The multivibrator is composed of the IC2 and R3，RP2，C3，C4, this multivibrator produces the oscillation frequencies of 0.5Hz～187Hz and 106Hz～41.2kHz. IC1 can modulate the IC2. By controling the K2，K3，K4 and K5, we can get the different modulation waves. If you connect the infrared glowing tube D5 to this circuit, this circuit can output the infrared modulation wave. When the K6 is in the position of 2 , the signal is amplified by VT2 and is boosted by T2, the secondary stage of T2 can produce the anion with the high-pressure corona method.   (View)

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555 frequency and duty ratio adjustable electronic therapeutic equipment circuit

Published:2011/5/24 1:29:00 Author:TaoXi | Keyword: frequency, duty ratio, adjustable, electronic therapeutic

As the figure 16-22 shows, the electronic therapeutic equipment is composed of the pulse generator, the voltage comparator, the amplifier stage and the power supply. The step-down rectifier circuit can produce the voltage of VDD=+8V and E2=+40V as the electronic therapeutic equipment's power supply. The astable multivibrator is composed of the IC1, R5，RP3，C2 and the constant-current tube D3, the oscillation frequency f=1.44/(R5+RP3)C2, you can change the frequency by adjusting RP3. D3 uses the 2DH type constant-current tube to guarantee the linearity of C2's charging sawtooth voltage. IC2 uses the LA2400 voltage comparator. VT1 and VT2 uses the VMOS type power amplifier tube. The voltage is output by the two channels of Jacks CK1 and CK2.   (View)

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555 patient faint language alarm box circuit

Published:2011/5/25 3:47:00 Author:TaoXi | Keyword: 555, patient, faint, language alarm, box

The language alarm box is composed of the posture switch, the oscillating circuit and the language alarm circuit, as the figure 16-43 shows. The astable multivibrator is composed of the IC1(555) and R3，R4，C2.etc. In the peace time, C2's voltage is lower than 1/3VDD, this makes the 555 in the setting state; when the patient falls down, SK makes the VT1 in the saturated conduction state, VT2 cuts off, C2's charging voltage is higher than 2V to make the D1 to cuts off. The IC2 uses the language integrated circuit IVR1601, this chip is composed of the clock circuit, the logic control circuit, the trigger circuit, the language read-only memory (ROM) and the driver.etc.   (View)

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555 alpha/theta meditation device circuit

Published:2011/5/25 4:03:00 Author:TaoXi | Keyword: 555, alpha, theta, meditation device

The design principle of the alpha/theta meditation device depends on human have different brain waves in different conditions, it can produce the flashing light which has the same frequency with the alpha/theta wave to make the brain wave in the resonance oscillation state, so people feel good, the circuit is as shown in figure 16-9. The table 16-1 shows the brain wave frequencies of different conditions. When you feel good, the brain wave frequency is the alpha wave. The astable multivibrator is composed of the 555 and R2，R3，RP1，C2, f=1.44/(RP1+R2+2R3)C2, the oscillation frequency is between 2～20Hz. The output of 555 gets through the VT1, and makes the VT1 issues the 7-14Hz flashing light.   (View)

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555 kitchen ventilator self controlled switch circuit

Published:2011/6/3 8:19:00 Author:nelly | Keyword: kitchen ventilator, self controlled switch

As shown in the figure 12-29, this switch is self-control, when the north wind blows, the switch can automatically turns on/off intermittently, the harmful gas will be discharged to outdoor, it avoids the gas filling into bedroom. If K1 is closed due to the wind, IC1, IC2 are set, the output terminal is high level, VT1 turns on, J pulls in, suction fan runs. At the same time, C3 is charged by RP1, when it is charged to 2/3 VDD of the threshold value level, IC2 is reset, J is discharged, the ventilator stops to running. If the wind power decreases, switch K1 cuts off, then IC1 automatically resets by td1. If the wind power does not decrease, K1 is still closed, then two monostable circuit trigger and set again, ventilator starts again. In other words, the on/off time of K1 is decided by the outside wind direction and the wind power.   (View)

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