LONG LIFE BATTERY-light modulator
This design project does not use photocells or photosensitive devices, but rather provides power or control devices for some of the projects discussed previously.A similar device sold in shops is called a light organ. People connect it to a stereo radio and can drive a set of color lights synchronously with the music or sound information produced by the stereo system.
Figs. 4 - 60 are the circuits of the light modulator.The audio signal generated by one system is changed into a light change in another system.The control element in the circuit is a 1 - ampere - figure 0 light modulator circuit
Pei's silicon controlled rectifier, which can modulate incandescent lamps or other direct current loads below 100W.This kind of circuit is quite simple. The low-power silicon controlled rectifier does not need additional cooling fins. It is mounted on the perforated circuit board together with the audio transformer and fuse.The audio signal sent from the speaker is connected to this circuit through a transformer %.The input lead of the transformer is connected across the terminal of the speaker.The secondary of the transformer adds a pulse signal between the control pole and the cathode of the thyristor.Bi controls the conduction of SCR by adjusting the trigger signal of SCR.The strong audio signal makes the thyristor fully conductive, while the weak signal only makes the thyristor partially conductive.The size of the conduction angle can change the luminous intensity of the incandescent lamp connected to the circuit socket.
Figs. 4 - 61 show the arrangement of components on the circuit board.Illustration;The connection of.The three leads from the transformer and silicon controlled rectifier are connected to RI and RA mounted on the circuit board of boxplot 4 - 61 light modulator components.
On the child.There are also wires on the circuit pole to the power plug, socket and the input of the speaker.All components are mounted on a perforated circuit board 2 inches square.
4 - 50 debugging steps
Referring to figs. 4 - 62, the circuit board is mounted in a small aluminum box.Connect all leads to the circuit board, socket, input terminal, and only the wire.Before the circuit is powered on, be sure to turn Si to the OFF position.After the above work is done, the RI can be turned until the bulb lights up and the D bulb lights up, indicating that the circuit is working.If the light bulb is not lit, it may be?\ Fused or Si is not closed, or silicon controlled rectifier may be damaged.Turn the bulb in the opposite direction to darken it until it is completely extinguished.Connect the lead of the speaker to the circuit input, and then tune the stereo radio to a radio station or play a tape or record, at which time the light bulb should shine again.It is possible that the brightness of the lamp will not change with the high level of music sound, and this will require further reverse rotation until the light intensity can change with the change of music rhythm and volume.Is a sensitivity controller that controls the light modulator to react differently to different volume levels.
This circuit can also be used in signal generators, audio amplifiers or other audio output sources to provide varying light intensity for photosensitive devices.The pulse audio signal is sent to the input of the modulator, which can also make the photosensitive circuit pulse.
This circuit converts audio signals into video signals.Some of the electronic circuits mentioned earlier convert video signals into sound or voltage pulses or even measurement pulses.
4 - 51 solar powered toy " windmill"
The design project mentioned in this section is of no use. It is proposed purely for the fun of the producer and is also one of the simplest circuits. It takes only 15 minutes to make it and ensures that it can work normally every time.Figure 4 - 63 shows a solar powered toy " windmill".The windmill rotates every time sunlight hits the surface of a single solar cell.In the figure, a toy motor is mounted on a bracket, which can be a scribing board or a cardboard box, or anything that can be inserted into the motor support by drilling holes in it, or anything that can be adhered to the motor support by epoxy resin.It only needs a 125 milliampere solar cell to turn.
The installation mode of the motor can be arbitrarily selected.Cut out the circuit of the rotary table powered by solar energy in fig. 4 with a piece of light hard paper.
A disc, which can be painted with beautiful colors, is glued to the shaft of the tractor with a drop of epoxy resin, so that when the windmill rotates, the disc will not slide from the shaft so that the disc can rotate with the shaft.The entire electrical wiring of this device has only two solar cell power lines.After the fabrication work is completed, when the surface of the solar cell is illuminated by bright light, the motor starts to rotate, and when the light disappears, the motor stops rotating.
This device is preferably installed on the windowsill where the sun's light energy shines, and the motor rotates quickly or slowly with the intensity of the sun's light.
If the reader is interested, he can install the motor on a small track racing car or other types of toy cars.The solar cell is mounted on the top of the toy, thus becoming a fun solar toy.If three solar cells are used, only 30 milliamperes of current is needed to turn the motor.The current will increase when the voltage decreases.
4 - 52 dimmer power supply
Fig. 4.64 is a device for changing the output voltage of 115 volts ( 1 ) household power supply with light intensity.It can output a stable DC voltage as a power supply for the transistor circuit.Different output voltages are achieved by changing the intensity of light.
As can be seen from the figure, the light control circuit has four photoresists connected in parallel to the output of the power supply and connected in series with the bulb and the power supply line.When the light intensity increases, the resistance value of the photoresistor decreases and the voltage drop across the photoresistor decreases.When the light becomes dark, the resistance value increases, reducing the output voltage or even no voltage output at all.
The voltage of the instrument panel lamp is 6V.This circuit generates a voltage drop only when an electronic load is connected, that is, when the load current passes through the photosensitive resistor, the voltage drop will be caused.
The primary voltage of the transformer is 115 volts and the secondary voltage is 12.6 volts.There is a midpoint tap at the secondary.Using a full-wave rectifier circuit with a midpoint tap and using a 500μ ① 115V is the standard of American household appliances, while the standard in China is 220V. Therefore, the number of turns of high voltage windings should be increased proportionally when winding transformers?- the translator's note method of electric filter.At no load, the voltage measured on the capacitor is about 11V, and the voltage supplied to the load can be adjusted according to the light intensity irradiated on the photoresistor.If the light is adjusted very dark or the light is completely blocked, no current flows through the load and the output voltage is zero.When the brightness gradually increases, the voltage starts to rise, and the output voltage can be adjusted to about 9V when the load current is very small.In general, this method is rarely used to control the output voltage. h is not practical, but this circuit can be used to explain the effect of resistors and photoresists on the voltage and current in electronic circuits.
The 6V instrument panel lamp is installed on the circuit board near the three photoresists, which is similar to the installation method of the photo-controlled car finder described earlier.Fig. 65 shows the arrangement of two rectifiers, capacitors, photoresists and instrument panel lamps on the circuit board. when the arrangement 0 is installed, the photoresists will be slightly deflected so that the light of the 6 volt instrument panel lamp can irradiate its surface more evenly.
Figure " 66 shows the circuit board installed in a small aluminum box.Installed at the bottom of the box, its primary coil is connected to the power feed fuse dance and power switch, its secondary coil is connected to the circuit board, and the midpoint tap of the transformer is connected to the aluminum box and the circuit board.
4 - 53 debugging steps
Turn the switch to the off position and insert the power plug into the socket.Turn counterclockwise to the end, and the resistance value is maximum at this time.Then use the test stick of voltmeter to lap the positive and negative poles of the output terminal, and then turn the switch to the on position. At this time, the electric FFI meter should indicate about 10V DC.After the electronic load is connected ( the load can use a 6V dashboard bulb that consumes 100mA of current ), turn on the power supply.If the light bulb is used as the load, the light bulb should not be lit.Slowly rotate clockwise, and the bulb at the power output should gradually become brighter.If other loads are connected to the output terminal, the voltage value at the output terminal should rise. If the voltage does not drop, the instrument panel lamp can be brought closer to the photoresistor. If the circuit does not work and there is no output voltage during the initial debugging, the instrument panel lamp installed on the circuit board should be checked.The resistance value of RI should be set to a minimum, and the instrument panel light should illuminate.Otherwise, there may be problems with rectifiers, capacitors and photoresistors. Rectifiers and capacitors are components with polarity. If the polarity is reversed, the whole circuit will not work.
If the instrument panel light is not on, the transformer is not working. This may be due to an accidental fuse blow, a disconnection between the power cord and the power outlet, or a damage.Be sure to find out whether there is electricity supply in the power socket of Ying, by inserting a good light bulb.Also check whether the wiring between the switch and the fuse holder is disconnected.
Once the circuit works properly, it can be used to supply power to electronic circuits that do not require precise voltage regulation.The dimming power supply in this section is not suitable for some solid-state circuit devices using integrated circuits or transistors because the variation of load current will cause fluctuations in the output voltage of such circuits, thus affecting the normal operation of solid-state circuits.
4 - 54 Light Remote Control Turtle Position Meter
In section 4 - 30 above, the control device for automatically interrupting the sound broadcast of commodity broadcasting is described, while in this section, the design content is that the reader can control the volume of a nearby TV, stereo or radio without leaving the seat.This kind of electronic circuit is not complicated, but some complicated relay wiring is needed in order to sweep the potentiometer in both directions to adjust the high and low volume.
The circuit is shown in figs. 4 - 67.In many ways, it is similar to the previously designed solar cell switch circuit.In fact, this is a copy of the solar cell switch circuit, in duplicate, used to control the two relays.Relays are double - pole, double - throw, double - pole, single-throw relays are better because double - pole, single-throw relays are not easy to buy. In the figure, double - pole, double-throw relays are replaced by double-pole, single-throw switches, and half of the contacts in each relay are unused.
The main part of this circuit is a small motor with 2 revolutions per minute, which is powered by a 3 volt DC power supply with 2 batteries connected in series.The operating current of the motor is less than 15ma.The electronic circuit part is powered by batteries for two sets of 9 volt transistor radios.It is also possible to connect the circuits in parallel, thus saving one set of batteries, but using two sets of batteries can prolong the working time of the circuit.
The small motor is reversible. Circuit A rotates the motor in one direction and circuit B rotates the motor in the other direction.When the light beam hits the POI surface of circuit A, the contact of 2 is closed, supplying power to the motor, and the motor starts to rotate.As long as the light beam can shine on it, the motor rotates continuously.To adjust the volume in the opposite direction, just move the beam from po *?03.Since POX has no illumination, the contact of the motor is opened and the motor stops rotating. When illumination is applied to PCA, the contact of the motor is closed and the power supply is applied, but the polarity is reversed at this time. Therefore, the motor must pay attention to rotating D in the opposite direction. Do not shine the light beam on P ( \ and 1 3 at the same time, because doing so will short-circuit both ends of the battery.This sum of 1 is used to adjust the sensitivity of each circuit to light.It should be adjusted so that only the focused beam can trigger the relay. If the sensitivity is not properly adjusted, it is possible to trigger both circuits simultaneously under normal indoor lighting conditions, which is not allowed to happen.
Figs. 4 - 68 show the arrangement of components on a circuit board.Only relays, transistors and batteries for circuits are installed on the circuit board / therefore, the area of the circuit board need not be too large.The circuit board is mounted in a plastic or aluminum box with some components mounted on the box and connected to the circuit board by wires.Figure 4 - 69A. The panel layout of the box.PCI is installed at one end of the panel and P0A is installed at the other end of the panel, so that when one light source is used to illuminate the solar cell, two circuits can be prevented from being triggered at the same time.Variable resistors are installed above and below the corresponding solar cells.The double-pole single-throw switch is well mounted in the middle of the panel, and SI is used to control two electronic circuits.
Figs. 4 - 69b are side views of the box.The circuit board is bolted close to the rear wall.The battery as the motor power supply is mounted on the battery holder under the circuit board.The relay should be connected to the motor and battery with a lead wire, and the lead wire of the motor should be led out of the box with a double-core cable.The connection of other wires shall be made as shown in Figure 4 - 67.
Figs. 4 - 70 show that mi is mounted on the panel of the device that needs it to be controlled, and the bottom of the motor has legs on both sides, so it can be firmly fixed as shown.The motor shaft and the potentiometer shaft are connected by a sleeve rolled with aluminum as a coupling, or the coupling can be made by tightening cellophane tape.
4 - 55 Debugging Steps
Si is placed in the off position.Connect all wires to the battery, motor and solar cell.Do not connect the motor shaft to the potentiometer for the time being.Fix the circuit board and box in the mounting position and adjust ugly 1 and 1 to the maximum resistance value.The indoor light cannot be too bright at this time.Cover a solar cell with your hand and close the switch at the same time. At this time, the motor should not rotate.If the motor starts to rotate and no abnormal reason can be found, the light in the room is too bright.It is possible to adjust the variable resistance of solar cells that are not covered by hand until the motor stops rotating.If the variable resistance is adjusted anyway and the motor is still rotating, the resistance values of RI and 112 are too small.Cut off the power supply to the circuit and replace RI and with a 25 kiloohm or 50 kiloohm variable resistor.If such a large resistance value is used and the sensitivity is in a critical state, a variable resistance with a slightly smaller resistance value can be used … If the motor does not rotate during the start of commissioning, the RI and private resistance values are just suitable.At this time, another solar cell can also be exposed to indoor light, and the motor should still not rotate.Then one of the variable resistors can be adjusted until the motor starts to rotate, and then the variable resistor is adjusted back until the motor stops rotating again.The same adjustment process is performed on the other variable resistor.
Use a flashlight to shoot a narrow beam at one of the two solar cells, and the motor should start rotating.If you don't rotate, you can slightly reduce the two variable resistors.Then aim the light beam at a solar cell and the motor starts to rotate.Turn off the flashlight and the motor should stop rotating.Similarly, aim the flashlight beam at another solar cell and repeat the above debugging steps.
During debugging, if it is found that no matter which solar cell operates, the motor always rotates in the same direction, it is likely that there is an error in the wiring between the relay contacts, B8 and B4 and the motor leads.If it is found that the motor is not running at all, check and!Whether or not to suck.If the relay operates, you can hear a " click" sound.If you can't hear the sound, it may be that the field and island fail or the wiring is wrong.Always check the surname and gen to ensure that the battery works effectively.
After the circuit debugging is normal, the motor can be connected to any type of volume control circuit to realize remote control.If the reversible motor is connected to the tuner shaft of the radio, the radio can be tuned.Several motors can be used at the same time to remotely control the volume, frequency response and tuning of the stereo receiver.