CN2671263Y - Starting up demagnetizing circuits - Google Patents
Starting up demagnetizing circuits Download PDFInfo
- Publication number
- CN2671263Y CN2671263Y CN 200320115256 CN200320115256U CN2671263Y CN 2671263 Y CN2671263 Y CN 2671263Y CN 200320115256 CN200320115256 CN 200320115256 CN 200320115256 U CN200320115256 U CN 200320115256U CN 2671263 Y CN2671263 Y CN 2671263Y
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- China
- Prior art keywords
- circuit
- electric capacity
- thermistor
- capacitor
- control circuit
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- Expired - Fee Related
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Abstract
The utility model discloses a starting up demagnetizing circuit whose aftercurrent is zeroth aiming at the problem that the aftercurrent is not zeroth in the traditional demagnetizing circuit. The starting up demagnetizing circuit comprises a demagnetizing coil 1, a thermosensitive resistor TH601 and a control circuit which are connected in series. The control circuit is used for adding the alternating current power supply on the demagnetizing coil 1 and the thermosensitive resistor TH601 or making the alternating current power supply be disconnected with the demagnetizing coil 1 and the thermosensitive resistor TH601. The demagnetizing circuit demagnetizes the CRT only at the starting up moment, and then the power supply is disconnected. The reliable demagnetization with conservation of energy is realized.
Description
Technical field
The utility model relates to a kind of degaussing circuit in picture tube or the display that is used for, and specifically, relates to a kind of controlled start automatic degaussing circuit.
Background technology
Color television set just develops towards the high definition direction, as the vitals of colour TV--chromoscope, must satisfy the requirement of colour purity.But because parts such as the radome of colour TV, shadow mask, aperture plate all are to be made by metal material; meeting is magnetized because of the effect in the magnetic field of earth magnetism or electrical equipment generation on every side; make the movement locus of electron gun emission R, G, three electron beams of B that unnecessary departing from can take place; can not meet on R, G, the B phosphor pixel; cause color unusual, normal TV reception when serious.For addressing this problem, in television set, be provided with interior degaussing circuit, when television boot-strap, work, carry out demagnetization, prevent because of of the influence of the outer stray magnetic field of earth magnetism or machine the electron beam deflecting.Traditional degaussing circuit is made of thermistor of anti-magnetized coil series connection, and the power supply of this degaussing circuit is directly provided by the AC power of television set.When the manual unlocking TV set power switch, alternating current is by thermistor and anti-magnetized coil, because thermistor is a positive temperature coefficient resistor, when initial, the resistance of thermistor is very little, the alternating current that flows through in thermistor and the anti-magnetized coil is very big, along with the lengthening of conduction time, the temperature of thermistor raises rapidly, makes the resistance of thermistor become big, thereby the alternating current that flows through in the anti-magnetized coil is diminished, and finally maintain on the more stable aftercurrent.So what flow through in the anti-magnetized coil is the electric current that successively decreases of alternation, the electric current that successively decreases of this alternation produces a magnetic field that reduces gradually around anti-magnetized coil, thereby reaches the purpose of demagnetization.But there is following defective in this degaussing circuit:
1) resistance of thermistor can not be infinitely great, causes to have an aftercurrent in the anti-magnetized coil all the time when television set is worked, and new magnetization influence is caused to the metal parts of television set in the magnetic field that this aftercurrent produces;
2) thermistor is in the state of being heated and keeping uniform temperature always when television set is worked, if during the situation of the very fast start again of television set shutdown just, owing to erasing current causes erasure effect bad greatly inadequately;
3) because thermistor and anti-magnetized coil are in conducting state always, cause power dissipation, be unfavorable for energy-conservation.
Summary of the invention
The purpose of this utility model provide a kind of can when start produce short time demagnetization and erasing time later aftercurrent be zero controlled start degaussing circuit.
For achieving the above object, a kind of start degaussing circuit that the utility model proposes, the anti-magnetized coil 1, thermistor TH601 and the control circuit that comprise series connection, control circuit are used for that AC power is added to anti-magnetized coil 1 and thermistor TH601 goes up or make AC power to disconnect from anti-magnetized coil 1 and thermistor TH601.
Described control circuit comprises switching circuit 4 and delay control circuit 5, one end of described switching circuit 4 links to each other with thermistor TH601, the other end links to each other with AC power, and described delay control circuit 5 links to each other with switching circuit 4, is used for being switched on or switched off of control switch circuit 4.
Further, described switching circuit 4 is a relay, described delay control circuit 5 includes transistor Q607, the first capacitor C 636B and the second capacitor C 637B, described first capacitor C 636B and second capacitor C 637B series connection, another termination DC power supply of the described first capacitor C 636B, the other end ground connection of the described second capacitor C 637B, the base stage of described transistor Q607 is connected series connection place of capacitor C 637B and capacitor C 636B, collector electrode connects switching circuit 4, grounded emitter.The capacitance of described capacitor C 636B is far longer than the capacitance of capacitor C 637B.
The beneficial effects of the utility model are: degaussing circuit is when start, and DC power supply is to capacitor C 636B and capacitor C 637B charging, and making transistorized base stage is high level, make transistor turns, the relay switch closure, thus make alternating current flow through thermistor and anti-magnetized coil, carry out demagnetization.When charging finishes, the electric capacity two ends just do not have potential difference to be zero potential, base stage at transistor Q607 does not have voltage like this, and the DC biased level of base stage promptly can not be provided for transistor Q607, makes transistor Q607 end, thereby relay switch is disconnected, no alternating current flows through thermistor and anti-magnetized coil, stops demagnetization, has realized carrying out when start demagnetization, after (about 1 second), degaussing circuit cuts off the power supply when the electric capacity charging finishes.Thereby realized reliable and energy-saving ground demagnetization.
Feature of the present utility model and advantage will be elaborated in conjunction with the accompanying drawings by embodiment.
Description of drawings
Fig. 1 represents circuit diagram of the present utility model.
Embodiment
Of the present utility model a kind of enforcement circuit as shown in Figure 1, anti-magnetized coil 1 is connected with AC power with thermistor TH601 series connection back one end in this circuit, and the other end links to each other with the switching circuit 4 that is made of relay.Relay is controlled the break-make of degaussing circuit and AC power like this.Described delay control circuit 5 includes transistor Q607, the first capacitor C 636B and the second capacitor C 637B, described first capacitor C 636B and second capacitor C 637B series connection, connect DC power supply behind the other end series resistance R631B of described resistance R 631B and the catching diode ZD604B, the other end ground connection of described capacitor C 637B, the base stage of described transistor Q607 is connected series connection place of capacitor C 637B and capacitor C 636B, collector electrode connects switching circuit 4, grounded emitter, also comprise diode D616P, the plus earth of described diode D616P, negative pole is connected series connection place of capacitor C 637B and capacitor C 636B, is used for discharge.During start, the high level of 15V is added to the base stage of transistor Q607 again by the voltage stabilizing of the 6.2V of voltage stabilizing didoe through resistance R 631B, capacitor C 636B, capacitor C 637B.The principle of utilizing the voltage at electric capacity two ends not suddenly change, this high level is to capacitor C 636B and capacitor C 637B charging.But the time lag of setting up high level on capacitor C 636B is in the available machine time.Because capacitor C 636B is far longer than capacitor C 637B, about value of charge constant is: the resistance of t=resistance R 631B multiply by the appearance value of capacitor C 636B, time constant is very big, and best parameter collocation is that the appearance value of capacitor C 636B is 220 μ F, and the appearance value of capacitor C 636B is 10 μ F.This high level makes transistor Q607 conducting, and then the current path on relay R L601 coil forms, and the AC power 220V of contact switch closure, degaussing circuit connects, and finishes the demagnetization action.Treat that capacitor C 636B charging finishes, the electric capacity two ends just do not have potential difference to be zero potential, base stage at transistor Q607 does not have voltage like this, the DC biased level of base stage promptly can not be provided for transistor Q607, make transistor Q607 end, relay R L601 goes up no current and flows through, and contact switch disconnects, in order to demagnetization next time.
This degaussing circuit only carries out demagnetization in the moment of starting shooting to picture tube, and then power supply disconnects, and has avoided field-discharge resistance to be in little operating state always, has both reduced meaningless power consumption, has prolonged the useful life of field-discharge resistance again, has reduced the temperature rise in the television set simultaneously.
Claims (6)
- One kind the start degaussing circuit, comprise the anti-magnetized coil (1) and the thermistor (TH601) of series connection, it is characterized in that: also comprise being used for being added to AC power on anti-magnetized coil (1) and the thermistor (TH601) or making the control circuit of AC power from anti-magnetized coil (1) and thermistor (TH601) disconnection.
- 2. start degaussing circuit as claimed in claim 1, it is characterized in that: described control circuit comprises switching circuit (4) and delay control circuit (5), one end of described switching circuit (4) links to each other with thermistor (TH601), the other end links to each other with AC power, described delay control circuit (5) links to each other with switching circuit (4), is used for being switched on or switched off of control switch circuit (4).
- 3. start degaussing circuit as claimed in claim 2 is characterized in that: described switching circuit (4) is a relay.
- 4. start degaussing circuit as claimed in claim 2, it is characterized in that: described delay control circuit (5) includes transistor (Q607), first electric capacity (C636B) and second electric capacity (C637B), described first electric capacity (C636B) and second electric capacity (C637B) series connection, another termination DC power supply of described first electric capacity (C636B), the other end ground connection of described second electric capacity (C637B), the base stage of described transistor (Q607) is connected series connection place of electric capacity (C637B) and electric capacity (C636B), collector electrode connects switching circuit (4), grounded emitter.
- 5. start degaussing circuit as claimed in claim 4 is characterized in that: the capacitance of described electric capacity (C636B) is far longer than the capacitance of electric capacity (C637B).
- 6. start degaussing circuit as claimed in claim 5 is characterized in that: the capacitance of described electric capacity (C636B) is 220 μ F, and the capacitance of described electric capacity (C637B) is 10 μ F.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200320115256 CN2671263Y (en) | 2003-12-02 | 2003-12-02 | Starting up demagnetizing circuits |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200320115256 CN2671263Y (en) | 2003-12-02 | 2003-12-02 | Starting up demagnetizing circuits |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2671263Y true CN2671263Y (en) | 2005-01-12 |
Family
ID=34475264
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200320115256 Expired - Fee Related CN2671263Y (en) | 2003-12-02 | 2003-12-02 | Starting up demagnetizing circuits |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2671263Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100438636C (en) * | 2005-09-14 | 2008-11-26 | 深圳创维－Rgb电子有限公司 | Time-controlling and magnetism-eliminating device |
-
2003
- 2003-12-02 CN CN 200320115256 patent/CN2671263Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100438636C (en) * | 2005-09-14 | 2008-11-26 | 深圳创维－Rgb电子有限公司 | Time-controlling and magnetism-eliminating device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |