LONG LIFE BATTERY-Chapter IV Solar Electronic Circuits
Chapter IV Solar Electronic Circuits
After introducing the tools, components and manufacturing techniques used in solar electronic circuits, we will discuss the design of electronic circuits by referring to IE.This chapter will recommend 33 kinds of electronic circuit designs with different complexity to readers.All the designs use solar cells, photoresists, phototransistors, or combined optoelectronic devices.As far as possible, the models and specifications of electronic devices that are not common or not easily available are also described in this book.Most of the solar cells used in many of these designs ( unless otherwise specified individually ) have no special requirements for the specifications of the devices.In most designs, only low-power solar cells are required;Of course, high-power solar cells are also suitable, but they are much more expensive.Therefore, according to the design, only electronic circuits powered by solar cells with smaller rated current are needed, and no high-power solar cells are needed.
The layout plan ( or installation plan ) and schematic diagram of most design schemes are drawn in one place, which will give readers a clear concept of where the components are most conveniently wired on the circuit board.Some designs are directly installed in plastic boxes, so no printed circuit board is needed. The installation drawings in the boxes are also drawn in this chapter.
If the reader is not clear about the legend symbol used in the circuit diagram, please refer to appendix a.It must be pointed out / do not make any electronic circuit before all necessary electronic devices are ready.It is necessary to study the circuit diagram and work out the production plan step by step, and prepare all the components before making the preparation for 4 - 1 production.
Every electronic circuit recommended in this chapter has been checked and practiced in detail.When the reader assembles according to the drawing, the working characteristics of each selected component must meet the design requirements in the book.Of course, there may be some differences in the characteristics of the products produced by different manufacturers, however, not many of them affect the working condition of the circuit due to such differences.Therefore, before manufacturing, it is necessary to carefully measure its parameters with instruments for each component in order to obtain its correct data.Especially for those components that deal with commodities, the data marked on their shells may be wrong;Although this kind of situation is not many, if it is used without clear understanding, it will add difficulties to the debugging work in the future.
There is no need to worry about the error of the marking parameter data on the components or the fact that the product parameters produced by different manufacturers vary greatly, which proves to be rarely encountered in the actual manufacturing process.Because the actual production proves that the first effect of the electronic circuit is mostly caused by poor soldering, it can be completely eliminated as long as it is done according to the production method described in the book.Another cause of circuit failure is wrong wiring.For example, if wire A should be connected to contact B, but accidentally connected to contact C, the circuit diagram should be checked repeatedly before welding to ensure that the wiring can be welded correctly.Once the electronic circuit has been manufactured, it must be carefully checked against the wiring diagram before the power supply is added. This is a necessary operating procedure.
The third reason for the failure of making electronic circuits is due to the use of failed components, including bad transistors, bad integrated circuits, broken wires and burned-out resistors.This can be done by using an ohmmeter to inspect various devices before fabrication.
When the electronic circuit is finished, it has already been said above that it must be checked carefully and the errors found and the ways to eliminate them should be recorded. This is a very useful experience.
4 - 2 Photovoltaic Exposure Meter
Photographers have long used exposure meters to determine the aperture and speed of cameras.Many of the early exposure meters used circuits similar to those shown in Figure 4 - 1.This is a circuit diagram combining a low-power photovoltaic cell or solar cell with a simple exposure meter. Sometimes a variable resistor is connected in series in the circuit. When aiming at a known light source, the variable resistor is used to cunning the ammeter.
The circuit of fig. 4 - 1 can be used to measure the brightness level of natural light and artificial light.This is a very simple device. If there is a meter, it can be made successfully in less than an hour. It can be seen from the figure that this circuit is composed of a power supply ( solar cell ), a microampere meter and a variable current limiting resistor connected in series.
M - 0 - 50 / IA ammeter PC,?Small solar cell f b - 50kql / 2w potentiometer fig. 4 - 1 photovoltaic exposure meter circuit
When a solar cell is exposed to light of a certain intensity, a current is generated in the circuit.The variable resistor is used to correct the pointer of the meter, and the pointer lives at the center position or evanescent microampere of the meter, and the light intensity at this time we call it the reference light intensity.Now, without changing the value of the variable resistance, aim the solar cell at a new light source. For example, if the pointer on the meter indicates 12 microamperes, the brightness of the new light source is about half that of the reference light source.If the pointer in the header indicates a full scale of 50 microamperes, it means that its brightness is twice that of the reference light source.The above example assumes that the frequencies of the two light sources are the same as compared to each other, because the conclusion is correct only when the frequencies are the same.
In the upper right corner of fig. 4 - 1 is the connection of the 50,000 ohm potentiometer in the circuit.Potentiometers control resistance values in two directions or in two circuits.The potentiometer in the figure is actually used as a variable resistor.The variable resistor changes the resistance value in only one circuit.- only the potentiometer has three contacts ( as shown in the figure, but only its two contacts are used here.When the potentiometer is used as a variable resistor, usually only the right contact and the middle contact are used ( the axis of the potentiometer is viewed against itself ), so that the axis of the potentiometer can rotate clockwise from left to right, and the pointer of the meter also rotates clockwise from left to right, because according to the connection of the two contacts, the resistance value of the potentiometer decreases when rotating clockwise.When the potentiometer rotates in the other axial direction ( counterclockwise ), the pointer in the meter rotates from right to left, i.e. reduces its reading.If the left and middle terminals are used, when the potentiometer is rotated clockwise, the reading on the meter head drops instead.Therefore, if the connection method is different, the reaction result is exactly the opposite.Both connections work well, but people are used to increasing the amount of control when they rotate clockwise from left to right.Just like the volume control of the radio or the dimming control of the lighting lamp.