CN104374472A - Ambient light illumination detecting device - Google Patents

Abstract

The invention discloses an ambient light illumination detecting device which comprises a 3V direct current power source, a photovoltaic conversion circuit and a differential amplifying and state display circuit. The photovoltaic conversion circuit is composed of a photoconductive resistor RG and a trimmer potentiometer RP. The model of the photoconductive resistor RG is MG44-03. The differential amplifying and state display circuit is formed by an NPN type transistor VT1, a green LED1, an NPN type transistor VT2, a red LED 2, a resistor R1, a resistor R2 and a resistor R3. The ambient light illumination detecting device is not influenced by changes of direct current power source voltage, changes of the environment temperature and the like. Although a circuit structure is simple, the working performance is reliable and stable, the requirements for ambient light illumination detection light and display of the detection light can be met, and students can be effectively instructed to read books and study under suitable light. The ambient light illumination detecting device is also suitable for the ambient light illumination qualitative light detection work.

Description

Ambient light illumination pick-up unit

Technical field

The invention belongs to illumination and light field of measuring technique, relate to a kind of ambient light illumination pick-up unit.

Background technology

When teenager sees written word, if do not note the power of ambient light, reading study under the too dark environment of light for a long time, will increase the weight of the burden of eye eye, easily suffer from the eye illnesses such as myopia in the course of time.

Ambient light illumination pick-up unit of the present invention is by NPN transistor VT1, differential amplifier circuit that NPN transistor VT2 is formed; its duty does not affect by the change of direct current power source voltage, the change etc. of environment temperature; although so the circuit structure of device is simple; but reliable working performance is stablized; ambient light illumination light-metering and display requirement thereof can be met completely; can effectively to read a book under suitable light study by instruction of papil, to protect the eyesight of teenagers eyes eye.

The circuit of ambient light illumination pick-up unit of the present invention is simple, and circuit all uses common components and parts, and cost of manufacture is low, is suitable for factory's batch production, is also suitable for the qualitative light-metering demand of ambient light illumination.

Below describe the core technology content that ambient light illumination pick-up unit of the present invention is involved in force in detail.

Summary of the invention

Goal of the invention and beneficial effect: the ambient light illumination pick-up unit described in invention is by NPN transistor VT1, differential amplifier circuit that NPN transistor VT2 is formed; its duty does not affect by the change of direct current power source voltage, the change etc. of environment temperature; although so the circuit structure of device is simple; but reliable working performance is stablized; ambient light illumination light-metering and display requirement thereof can be met completely; can effectively to read a book under suitable light study by instruction of papil, to protect the eyesight of teenagers eyes eye.The present invention is also suitable for the qualitative light-metering demand of ambient light illumination.

The principle of work of device circuit: in ambient light illumination pick-up unit circuit, photoelectric switching circuit is made up of photoresistance RG and trimmer potentiometer RP, and photoelectric switching circuit and NPN transistor VT2, resistance R2, resistance R3 form light-metering bridge diagram.Form differential amplifier circuit by NPN transistor VT1, NPN transistor VT2, resistance R1 is the current-limiting resistance of green LED LED1, red light emitting diodes LED2, is also the negative feedback common mode inhibition resistance of differential amplifier circuit simultaneously.

When ambient light illumination changes, the bias potential of NPN transistor VT1 can change along with the resistance of photoresistance RG and be elevated, and the bias potential that resistance R2, resistance R3 are supplied to NPN transistor VT2 is then changeless.

When ambient light illumination is stronger, photoresistance RG is low resistance, now NPN transistor VT1 obtains bias potential, make NPN transistor VT1 conducting, NPN transistor VT2 cut-off or trend cut-off, so green LED LED1 sends green glow, red light emitting diodes LED2 does not glow, representative ring environmental light becomes clear, and applicable used by students during reading writes.

When ambient light illumination is more weak, photoresistance RG is higher resistance value, the bias potential of NPN transistor VT1 is lower than the set potential of NPN transistor VT2, NPN transistor VT1 is ended, and make NPN transistor VT2 conducting, so green LED LED1 extinguishes, red light emitting diodes LED2 sends ruddiness, representative ring environmental light is too dark, should turn on electric light floor light or stopping in time and to read and write the activity of grade.

Accompanying drawing explanation

Accompanying drawing 1 is the circuit working schematic diagram of an ambient light illumination pick-up unit of the present invention embodiment.

Embodiment

According to the ambient light illumination pick-up unit circuit working schematic diagram shown in accompanying drawing 1 and accompanying drawing explanation, and according to annexation between components and parts in each several part circuit described in summary of the invention, and components and parts technical parameter described in embodiment requires and circuit production main points are carried out enforcement and can be realized the present invention, is further described correlation technique of the present invention below in conjunction with embodiment.

Technical characteristic: ambient light illumination pick-up unit, it comprises 3V direct supply, photoelectric switching circuit, differential amplification and status display circuit, it is characterized in that:

Photoelectric switching circuit: it is made up of photoresistance RG, trimmer potentiometer RP, the model that photoresistance RG selects is MG44-03, photoresistance RG one end and trimmer potentiometer RP mono-termination NPN transistor VT1 base stage, photoresistance RG other end connection circuit positive pole VCC, the trimmer potentiometer RP other end and movable end connection circuit ground GND thereof;

Differential amplification and status display circuit: it is by NPN transistor VT1 and green LED LED1, NPN transistor VT2 and red light emitting diodes LED2, resistance R1, resistance R2 and resistance R3 is formed, NPN transistor VT1 emitter and NPN transistor VT2 emitter are by resistance R1 connection circuit ground GND, base stage connecting resistance R2 one end of NPN transistor VT2 and resistance R3 one end, resistance R2 other end connection circuit positive pole VCC, resistance R3 other end connection circuit ground GND, NPN transistor VT1 collector connects green LED LED1 negative pole, NPN transistor VT2 collector connects red light emitting diodes LED2 negative pole, green LED LED1 positive pole and red light emitting diodes LED2 positive pole connection circuit positive pole VCC,

3V DC power anode is connected with circuit anode VCC, and 3V DC power cathode is connected with circuit ground GND.

The technical parameter of components and parts and selection requirement

The model that photoresistance RG selects is MG44-03, also can select the models such as MG45, and under the illuminance of 100Lx (lux), its bright resistance is in the photoresistance of other model of 5K about Ω;

Resistance all selects RTX-1/8W type, power to be 1/8W carbon resister, and the resistance of resistance R1 is 120 Ω, and the resistance of resistance R2 is 6.8K Ω, and the resistance of resistance R3 is 6.8K Ω;

RP is trimmer potentiometer, and its resistance is 12K Ω;

NPN transistor VT1, NPN transistor VT2 all use 2SC9014, require two Manifold technology parameter pairings, currentamplificationfactorβ >=180;

Green LED LED1, red light emitting diodes LED2 adopt high brightness green light emitting diode and the High brightness Red LED of ￠ 5mm respectively;

Pushbutton switch AN uses KJ-123 type touch switch, and physical dimension is 12mm × 12mm × 4mm;

Direct supply DC uses the SR44 type (￠ 11.6mm × 5.4mm) or the button-shaped miniature silver oxide cell of AG13, G13-A type that two Granule Computing devices are conventional, and the DC voltage after its series connection is 3V.

Circuit production and adjustment method

Because the circuit structure of ambient light illumination pick-up unit is fairly simple, as long as the electronic devices and components performance generally selected is intact, and the components and parts annexation to specifications in accompanying drawing 1 is welded, physical connection line and welding quality are through carefully checking correctly, this device can normally work as long as circuit carries out debugging a little after connecting 3V direct supply;

When circuit debugging, first the resistance of trimmer potentiometer RP is transferred to maximal value, blocks the light on photoresistance RG with cardboard, make photoresistance RG not receive light, because photoresistance RG is higher resistance value; Next slowly regulates the resistance of trimmer potentiometer RP that NPN transistor VT1 is ended, NPN transistor VT2 conducting, makes that green LED LED1 extinguishes, red light emitting diodes LED2 sends ruddiness;

Cardboard is left photoresistance RG, when ambient light illumination is stronger, photoresistance RG is low resistance, now NPN transistor VT1 obtains bias potential, make NPN transistor VT1 conducting, NPN transistor VT2 cut-off or trend cut-off, so green LED LED1 sends green glow, red light emitting diodes LED2 is not luminous, namely circuit debugging has accused;

Not gordian technique of the present invention as circuit components layout of the present invention, board design, outward appearance and size etc., neither the technology contents of application claims protection, therefore illustrate no longer one by one in the description.

Claims (1)

1. an ambient light illumination pick-up unit, it comprises 3V direct supply, photoelectric switching circuit, differential amplification and status display circuit, it is characterized in that:

Photoelectric switching circuit: it is made up of photoresistance RG, trimmer potentiometer RP, the model that photoresistance RG selects is MG44-03, photoresistance RG one end and trimmer potentiometer RP mono-termination NPN transistor VT1 base stage, photoresistance RG other end connection circuit positive pole VCC, the trimmer potentiometer RP other end and movable end connection circuit ground GND thereof;

Differential amplification and status display circuit: it is by NPN transistor VT1 and green LED LED1, NPN transistor VT2 and red light emitting diodes LED2, resistance R1, resistance R2 and resistance R3 is formed, NPN transistor VT1 emitter and NPN transistor VT2 emitter are by resistance R1 connection circuit ground GND, base stage connecting resistance R2 one end of NPN transistor VT2 and resistance R3 one end, resistance R2 other end connection circuit positive pole VCC, resistance R3 other end connection circuit ground GND, NPN transistor VT1 collector connects green LED LED1 negative pole, NPN transistor VT2 collector connects red light emitting diodes LED2 negative pole, green LED LED1 positive pole and red light emitting diodes LED2 positive pole connection circuit positive pole VCC,

3V DC power anode is connected with circuit anode VCC, and 3V DC power cathode is connected with circuit ground GND.