CN202453397U - Pointer galvanometer circuit with logarithm measurement feature - Google Patents
Pointer galvanometer circuit with logarithm measurement feature Download PDFInfo
- Publication number
- CN202453397U CN202453397U CN2012200315313U CN201220031531U CN202453397U CN 202453397 U CN202453397 U CN 202453397U CN 2012200315313 U CN2012200315313 U CN 2012200315313U CN 201220031531 U CN201220031531 U CN 201220031531U CN 202453397 U CN202453397 U CN 202453397U
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- Prior art keywords
- operational amplifier
- input end
- output terminal
- circuit
- negative input
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Abstract
Disclosed is a pointer galvanometer circuit with a logarithm measurement feature. The negative input end of an operational amplifier U in the circuit is in a series connection with a resistor R1 to be set as an signal input end IN, the positive input end of the operational amplifier U is grounded, the output end of the operational amplifier U is set as an signal output end OUT, and a forward diode D1 and a backward diode D2 are respectively in a parallel connection between the negative input end and the output end of the operational amplifier U. According to the circuit, the enlargement factor is large when signals are small, and decreases along with the increase of the signals; therefore overload of the galvanometer caused by overlarge input signals is avoided. The pointer galvanometer circuit has the advantages of being high in sensitivity and practicability, not easy to damage, and convenient to change the measuring range.
Description
Technical field
The utility model relates to a kind of eedle galvanometer circuit with logarithm measurement characteristics.
Background technology
Traditional eedle galvanometer is widely used in the occasion that various Weak currents detect, and like electric bridge, potential difference meter etc., all uses galvanometer as the indispensable instrument of measuring.What early stage galvanometer used is highly sensitive suspension-wire type coil, is easy in the use receive overload impact and damages.What the galvanometer in later stage made charged sub-amplifying circuit into is the galvanometer of indication with common microampere meter, and these galvanometers all can cause gauge outfit to be damaged in use because of overrange, and can have long problem overload back release time.
Summary of the invention
The utility model mainly is to solve above-mentioned existing in prior technology technical matters, and a kind of eedle galvanometer circuit with logarithm measurement characteristics is provided.
The above-mentioned technical matters of the utility model mainly is able to solve through following technical proposals: a kind of eedle galvanometer circuit with logarithm measurement characteristics comprises that one is operational amplifier U, the negative input end series resistor R of operational amplifier U
1After be set to signal input part IN, the positive input terminal ground connection of operational amplifier U, the output terminal of operational amplifier U is set to signal output part OUT, between the negative input end of operational amplifier U and the output terminal and meet the diode D of forward
1, between the negative input end of operational amplifier U and the output terminal and meet reverse diode D
2
The utility model principle is summarized as follows: resistance R
1, diode D
1, D
2Constituted a logarithmic amplifier with operational amplifier, can know according to the characteristic of operational amplifier and diode current and voltage characteristic:
I in the formula
SBe reverse saturation current, q is the electric charge constant, and k is a Boltzmann constant, and T is a thermodynamic temperature, and Uo is an output voltage, I
iBe input current, I
DBe the diode forward electric current.Logarithm is asked on formula (1) both sides, can be got:
Because I
SValue very little, so can ignore, formula (2) can be reduced to:
Because at a certain temperature, q, k, T are constant, but the output voltage of knowledge capital utility model circuit becomes logarithmic relationship with the relation of input current.
As preferably, go back and be connected to resistance R between the negative input end of said operational amplifier U and the output terminal
2, and R
2Much larger than R
1Between the negative input end and output terminal of operational amplifier U, diode D
1And D
2Common port series resistor R
3After be connected to the output terminal of operational amplifier U and resistance R
3Much smaller than R
2, R wherein
2Effect be to set galvanometric peak response, to be complementary with actual needs effectively; R
3Effect be the higher limit that electric current is measured in restriction, and the protection diode is unlikely to damage because of electric current is excessive; Change resistance R in addition
1, can change galvanometric range size.
The utility model circuit when small-signal has bigger enlargement factor, and along with the increase enlargement factor of signal diminishes, can overcome the excessive galvanometer overload that causes owing to input signal like this.Both had highly sensitive characteristics, and had non-damageable characteristics again, and its measurement range also can conveniently change, have very strong practicality.
Description of drawings
Fig. 1 is a kind of structural representation of the utility model;
Fig. 2 is a kind of improvement structural representation of the utility model.
Embodiment
Below by embodiment, and in conjunction with the accompanying drawings, do further bright specifically to the technical scheme of the utility model.
Embodiment: referring to Fig. 1, a kind of structure of the utility model is the negative input end series resistor R of operational amplifier U
1After be set to signal input part IN, the positive input terminal ground connection of operational amplifier U, the output terminal of operational amplifier U is set to signal output part OUT, between the negative input end of operational amplifier U and the output terminal and meet the diode D of forward
1, between the negative input end of operational amplifier U and the output terminal and meet reverse diode D
2
Referring to Fig. 2, the utility model a kind of improves between negative input end that structure is operational amplifier U and the output terminal also and is connected to resistance R
2, and R
2Much larger than R
1Between the negative input end and output terminal of operational amplifier U, diode D
1And D
2Common port series resistor R
3After be connected to the output terminal of operational amplifier U and resistance R
3Much smaller than R
2, R wherein
2Effect be to set galvanometric peak response, to be complementary with actual needs effectively; R
3Effect be the higher limit that electric current is measured in restriction, and the protection diode is unlikely to damage because of electric current is excessive; Change resistance R in addition
1, can change galvanometric range size.
The utility model circuit when small-signal has bigger enlargement factor, and along with the increase enlargement factor of signal diminishes, can overcome the excessive galvanometer overload that causes owing to input signal like this.Both had highly sensitive characteristics, and had non-damageable characteristics again, and its measurement range also can conveniently change, have very strong practicality.
At last, should be pointed out that above embodiment only is the more representational example of the utility model.Obviously, the utility model is not limited to the foregoing description, and many distortion can also be arranged.Every technical spirit according to the utility model is to any simple modification, equivalent variations and modification that above embodiment did, all should think the protection domain that belongs to the utility model.
Claims (2)
1. the eedle galvanometer circuit with logarithm measurement characteristics is characterized in that said circuit comprises that one is operational amplifier U, the negative input end series resistor R of operational amplifier U
1After be set to signal input part IN, the positive input terminal ground connection of operational amplifier U, the output terminal of operational amplifier U is set to signal output part OUT, between the negative input end of operational amplifier U and the output terminal and meet the diode D of forward
1, between the negative input end of operational amplifier U and the output terminal and meet reverse diode D
2
2. according to the said a kind of eedle galvanometer circuit of claim 1, it is characterized in that between negative input end and the output terminal of said operational amplifier U also and be connected to resistance R with logarithm measurement characteristics
2, and R
2Much larger than R
1Between the negative input end and output terminal of operational amplifier U, diode D
1And D
2Common port series resistor R
3After be connected to the output terminal of operational amplifier U and resistance R
3Much smaller than R
2
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012200315313U CN202453397U (en) | 2012-02-01 | 2012-02-01 | Pointer galvanometer circuit with logarithm measurement feature |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012200315313U CN202453397U (en) | 2012-02-01 | 2012-02-01 | Pointer galvanometer circuit with logarithm measurement feature |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202453397U true CN202453397U (en) | 2012-09-26 |
Family
ID=46869252
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012200315313U Expired - Fee Related CN202453397U (en) | 2012-02-01 | 2012-02-01 | Pointer galvanometer circuit with logarithm measurement feature |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202453397U (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103095237A (en) * | 2013-02-05 | 2013-05-08 | 天津大学 | High output amplitude mixer based on logarithmic amplifier |
| CN103095235A (en) * | 2013-02-05 | 2013-05-08 | 天津大学 | Mixer based on exponential amplifier |
| CN103117709A (en) * | 2013-02-05 | 2013-05-22 | 天津大学 | Log amplifier based mixer |
| CN103178795A (en) * | 2013-02-05 | 2013-06-26 | 天津大学 | Difference frequency indicator based on log amplifier |
| CN103178796A (en) * | 2013-02-05 | 2013-06-26 | 天津大学 | High-output amplitude difference frequency indicator based on log amplifier |
| CN110431434A (en) * | 2017-03-01 | 2019-11-08 | 索尔塔雷有限公司 | System and method for detecting target sound |
-
2012
- 2012-02-01 CN CN2012200315313U patent/CN202453397U/en not_active Expired - Fee Related
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103095237A (en) * | 2013-02-05 | 2013-05-08 | 天津大学 | High output amplitude mixer based on logarithmic amplifier |
| CN103095235A (en) * | 2013-02-05 | 2013-05-08 | 天津大学 | Mixer based on exponential amplifier |
| CN103117709A (en) * | 2013-02-05 | 2013-05-22 | 天津大学 | Log amplifier based mixer |
| CN103178795A (en) * | 2013-02-05 | 2013-06-26 | 天津大学 | Difference frequency indicator based on log amplifier |
| CN103178796A (en) * | 2013-02-05 | 2013-06-26 | 天津大学 | High-output amplitude difference frequency indicator based on log amplifier |
| CN103095235B (en) * | 2013-02-05 | 2016-03-09 | 天津大学 | A kind of frequency mixer based on exponential amplifier |
| CN103178795B (en) * | 2013-02-05 | 2016-05-18 | 天津大学 | A kind of difference frequency device based on logafier |
| CN103178796B (en) * | 2013-02-05 | 2016-05-25 | 天津大学 | A kind of high output amplitude difference frequency device based on logafier |
| CN103117709B (en) * | 2013-02-05 | 2016-05-25 | 天津大学 | A kind of frequency mixer based on logafier |
| CN103095237B (en) * | 2013-02-05 | 2016-08-03 | 天津大学 | A kind of high output amplitude frequency mixer based on logafier |
| CN110431434A (en) * | 2017-03-01 | 2019-11-08 | 索尔塔雷有限公司 | System and method for detecting target sound |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120926 Termination date: 20190201 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |