CN2286908Y

CN2286908Y - Instrument for demonstrating electric conductivity of matter

Info

Publication number: CN2286908Y
Application number: CN 97204086
Authority: CN
Inventors: 廖振威; 谭明清
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-01-20
Filing date: 1997-01-20
Publication date: 1998-07-29
Anticipated expiration: 2007-01-20

Abstract

The utility model relates to an instrument for demonstrating the electric conductivity of matter, which belongs to the models for teaching. The utility model provides a teaching appliance which can visually demonstrate the electrical conductivity and contrast of all matter. The electrical conductivity of the matter can be displayed by the brightness of a bulb, and a sensitivity selecting mode is provided to carry out contrasting experiments. The utility model has the advantages that the demonstrating effect can be enhanced; the relativity of the conductors and the insulators can be comprehended deeply. The utility model also has the advantages of obvious demonstrating effect, visual demonstration, simple circuit, low cost, convenient operation, controllable sensitivity, good repeatability, and easy maintenance. The utility model is characterized in that a module and the bulb are arranged in a box body; a power supply switch, power supply, a sensitivity regulating switch, a resistor, and a point which needs to be detected are formed into a whole circuit, a modular circuit, and a heating attachment by series connection.

Description

The substance conductance demonstrator

The utility model belongs to pedagogical model.

In China's existing People's Education Publishing House Senior Two physics teaching material, junior three physics teaching material, junior three chemistry teaching material, the primary school nature general knowledge, all relevant for the lecture experiment of substance conductance.Because the electric conductivity of various materials differs, cause quite a few experiment to be difficult to demonstration.Especially when the electric conductivity of demonstration human body, the earth, water etc., because their resistance is bigger, more than several kilohms, thereby ammeter pointer deflection is minimum, poor effect.Though recently having produced model by Jiaxing City, Zhejiang Province instrument accessory factory is the micro current amplifier of J2477, this class experiment there is certain help.But because this Instrument structure complexity, it is the reometer of 50 μ A that there is a range its inside, but also needs showing ammeter of adjunction, needs two power supplys to power simultaneously, the zeroing knob is arranged again, amplify adjusting knob etc., damages easily, and difference is amplified but unprotect; Not directly perceived, totally enclosed type, the student does not see circuit, and the internal current table is too little, and display effect is poor, so the demonstration effect is undesirable; On the high side, difficult again the repairing.

At the problems referred to above, the purpose of this utility model is to provide a kind of can demonstrate the electric conductivity of various materials and the instruments used for education of contrast intuitively.The electric conductivity of material shows by bright the showing slinkingly of bulb, and added sensitivity selecting switch and compare experiment.Improve the demonstration effect, deepen understanding conductor, insulator relativity.

The utility model is realized with following mode: feature is that it has box body 1, and module 2 is arranged in box body 1, this module 2 and bulb L, power switch S, power supply E and sensitivity switch K, resistance R ₂, testing resistance measuring point A, B serial connection constitutes integrated circuit, " 1 " contact inserts power supply E negative pole in this integrated circuit, " 2 " contact inserts testing resistance measuring point A and sensitivity switch K, and then connecting resistance R ₂One end, " 3 " contact inserts power supply E positive pole and resistance R ₂One end, " 4 " contact inserts bulb L, and bulb L is contained on box body 1 watchcase.Module 2 is by resistance R ₁R ₃, triode BG ₁BG ₂, the circuit that constitutes of capacitor C; Resistance R wherein ₁One end connects with " 2 " contact, in addition an end and the triode BG of end and capacitor C ₁Base stage links, end, the triode BG in addition of " 3 " contact and capacitor C ₁Emitter, power supply E positive pole link triode BG ₁Collector and resistance R ₃An end connect resistance R ₃In addition end and triode BG ₂Base stage link.Triode BG ₂Emitter and power supply E negative pole link, collector connects with " 4 " contact.This substance conductance demonstrator can also 1 of parallel connection heat annex 3 between testing resistance measuring point A, B, this heating annex 3 is by being made up of 1 vitreum between two leads.

Advantage of the present utility model is as follows: 1, the demonstration effect very obvious, with bulb bright show slinkingly show very directly perceived.2, circuit is simple, and is cheap.3, easy to operate, sensitivity may command, good reproducibility.4, the starting material source is wide, and for ease of maintenaince.

Now in conjunction with the accompanying drawings the utility model is described in further detail.

Fig. 1 is the utility model structural representation;

Fig. 2 is integrated circuit figure of the present utility model;

Among Fig. 3 module 2 circuit diagrams of the present utility model;

Fig. 4 is heating annex 3 structural representations of the present utility model.

With reference to Fig. 1-Fig. 3, in the utility model box body 1 integrated circuit is arranged, module 2 is serially connected in the integrated circuit.With reference to Fig. 3, Fig. 2, when sensitivity switch K disconnected, the resistance that is connected into test substance between testing resistance measuring point A, the B was less than or equal to 10 ⁶Ohm is right, triode BG ₁Base current bigger, through triode BG ₁, BG ₂After amplify at the two poles of the earth, triode BG ₂Saturation conduction, L is luminous for the lamp bag.If be connected into test substance resistance greater than 10 between A, the B ⁶During ohm, triode BG ₁Base current less, triode BG ₂Not conducting, bulb L is not luminous.When sensitivity switch K is closed, resistance R ₂Be connected on triode BG ₁The emitter of base stage on, reduced triode BG ₁Base current.Thereby reduced the sensitivity of this circuit.When resistance was less than 3000 ohm between A, the B, bulb just can be bright.With reference to Fig. 4, use heating annex 3, along A, the B place that the small arrow direction is slowly inserted Fig. 1, at this moment between A, the B just parallel connection Vitrea heating annex 3 is arranged between two leads.When sensitivity switch K disconnects, give with spirit lamp or other firing equipment on the vitreum of heating annex 3 and heat, after after a while, when vitreum became red vehement state, bulb L was not by original shinny to shinny.Like this, the teacher has just demonstrated the physical phenomenon that conductor and insulator can transform mutually under certain condition to the student.

Claims

1, a kind of substance conductance demonstrator is characterized in that:

It has box body [1], and module [2] is arranged in box body [1], this module [2] and bulb [L], power switch [S], power supply [E] and sensitivity switch [K], resistance [R ₂], testing resistance measuring point [A], [B] serial connection constitutes integrated circuit, " 1 " contact inserts power supply [E] negative pole in this integrated circuit, " 2 " contact inserts testing resistance measuring point [A], and sensitivity switch [K], and then connecting resistance [R ₂] end, " 3 " contact inserts power supply [E] positive pole and resistance [R ₂] ... end, " 4 " contact inserts bulb [L], and bulb [L] is contained on box body [1] watchcase;

Module [2] is by resistance [R ₁] [R ₂], triode [BG ₁] [BG ₂], the circuit that constitutes of electric capacity [C]; Resistance [R wherein ₁] end connects with " 2 " contact, an end and the triode [BG of end and electric capacity [C] in addition ₁] base stage links, end, the triode [BG in addition of " 3 " contact and electric capacity [C] ₁] emitter, power supply [E] positive pole link triode [BG ₁] collector and resistance [R ₃] an end connect resistance [R ₃] in addition end and triode [BG ₂] base stage link triode [BC ₂] emitter and power supply [E] negative pole link, collector connects with " 4 " contact.

2, substance conductance demonstrator according to claim 1 is characterized in that between testing resistance measuring point [A] [B] 1 heating annex [3] in parallel, and this heating annex [3] is by being made up of 1 vitreum between two leads.