阅读说明：本技术 用555定时器实现对有极性电解电容反接的保护电路 (Protection circuit for realizing reverse connection of polar electrolytic capacitor by using 555 timer ) 是由 李全民 于 2020-05-09 设计创作，主要内容包括：本发明的用555定时器实现对有极性电解电容反接的保护电路,包括电解电容E1、接线端JP1和电容反接保护电路,电容反接保护电路由场效应管Q1、555定时器、继电器JDQ、发光二极管LED、稳压二极管D1组成,Q1的栅极接于E1的正极上,555定时器的触发端和阈值端短接后再依次经电阻R1和JDQ的常开点接于E1的正极上,输出端经继电器JDQ的线圈接于电源正上；D1的正极接于电源地上,负极接于555定时器上。本发明的电容反接的保护电路,当E1接线错误时,保护电路会保持E1始终处于断开状态,实现了对E1的有效保护,并通过点亮LED来警示接线错误,避免了接线错误所导致的电容损坏、电容爆炸现象的发生。(The invention discloses a protection circuit for realizing reverse connection of a polar electrolytic capacitor by using a 555 timer, which comprises an electrolytic capacitor E1, a terminal JP1 and a capacitor reverse connection protection circuit, wherein the capacitor reverse connection protection circuit consists of a field effect tube Q1, a 555 timer, a relay JDQ, a light emitting diode L ED and a voltage stabilizing diode D1, a grid electrode of a Q1 is connected to an anode of an E1, a trigger end and a threshold end of the 555 timer are in short circuit and then are sequentially connected to an anode of an E1 through normally open points of a resistor R1 and the JDQ, an output end is connected to a power supply through a coil of the relay JDQ, an anode of a D1 is connected to a power ground, and a cathode 555 is connected to the timer.)

1. A protection circuit for realizing reverse connection of a polar electrolytic capacitor by using a 555 timer comprises a polar electrolytic capacitor E1 (1), a capacitor terminal JP1 (2) and a capacitor reverse connection protection circuit, wherein E1 is the polar electrolytic capacitor protected and connected to other circuits, JP1 has two terminals, and the positive electrode and the negative electrode of E1 are connected with two terminals of JP1, the protection circuit is characterized in that the capacitor reverse connection protection circuit comprises a field effect tube Q1 (2), a 555 timer (3), a relay Q (4), a light emitting diode L ED (5), a voltage stabilizing diode D1 and a direct current power circuit, the field effect tube Q1 is of N-channel enhancement type, the positive electrode of E1 is connected with JP1 through the normally open point of the relay JDQ, the grid of Q1 is connected with the positive electrode of E1, the grid of Q1 is connected with the source electrode of the normally open diode Q2, the source of Q1 is connected with the ground, the drain of Q1 is connected with the power supply resistor JDQ 3, the trigger resistor, the positive electrode of the power supply terminal of the power supply resistor JDQ 599 and the trigger terminal of the normally open resistor JDQ 463, the normally open resistor R1 is connected with the ground, the trigger terminal of the normally open resistor R8653 and the reset terminal of the normally open diode, the normally open resistor R8653 and the normally open resistor R8653 are connected with the reset terminal of the normally open resistor 4 and the normally open resistor.

2. A protection circuit for realizing reverse connection of a polar electrolytic capacitor by using a 555 timer as claimed in claim 1 or 2, wherein: the direct current power supply circuit is composed of a transformer TB (7), a three-terminal voltage regulator tube PV (8), an electrolytic capacitor E3, an electrolytic capacitor E2 and a full-bridge rectification circuit composed of diodes D3, D4, D5 and D6, wherein the primary side of the transformer is connected to an alternating current mains supply, the secondary side of the transformer is connected to the input end of the full-bridge rectification circuit, the anode of the output end of the full-bridge rectification circuit is connected to the input end of the three-terminal voltage regulator tube PV (8), and the output end of the three-terminal voltage regulator tube PV forms a; the electrolytic capacitor E3 is connected with the output end of the full-bridge rectification circuit, and the electrolytic capacitor E2 is connected with the output end of the three-terminal voltage regulator tube PV.

3. A protection circuit for realizing reverse connection of a polar electrolytic capacitor by using a 555 timer as claimed in claim 1 or 2, wherein: two ends of the coil of the relay JDQ (4) are connected in parallel with a diode D2 playing a role of freewheeling, the anode of the D2 is connected to the output end of the 555 timer (3), and the cathode of the D2 is connected to the power supply.

4. A protection circuit for realizing reverse connection of a polar electrolytic capacitor by using a 555 timer as claimed in claim 1 or 2, wherein: the resistance values of the resistor R1 and the resistor R2 are both 10k omega, the resistance value of the resistor R3 is 4.7k omega, and the resistance value of the resistor R4 is 100k omega.

Technical Field

The invention relates to a protection circuit for reverse connection of a polar electrolytic capacitor, in particular to a protection circuit for reverse connection of a polar electrolytic capacitor by using a 555 timer.

Background

The polar electrolytic capacitor has a positive terminal and a negative terminal, and can not be reversely connected during the use process because the electrolytic capacitor contains electrolyte materials for storing charges, and the electrolytic capacitor can be damaged if the electrolytic capacitor is reversely connected. When students in electrical profession are doing experiments, the electrolytic capacitors are used, and particularly in the process of designing a power supply filter circuit and teaching experiments, the students need to be connected with the electrolytic capacitors in person to fully understand and master the characteristics of the electrolytic capacitors. In the experimental process, the situation that the anode and the cathode of the electrolytic capacitor are reversely connected always occurs, once the polar electrolytic capacitor is reversely connected, the polar electrolytic capacitor is damaged slightly to influence the normal operation of the experiment, and explodes seriously to cause personal injury. Therefore, in some experimental circuits, reverse connection protection of the polar electrolytic capacitor is imperative. The 555 timer is an integrated circuit chip, can be used as a trigger, is a common device in the teaching process of an electronic circuit, and can realize reverse connection protection of the polar electrolytic capacitor by utilizing the 555 timer.

Disclosure of Invention

In order to overcome the defects of the technical problems, the invention provides a protection circuit for realizing the reverse connection of a polar electrolytic capacitor by using a 555 timer.

The invention discloses a protection circuit for realizing reverse connection of a polar electrolytic capacitor by using a 555 timer, which comprises a polar electrolytic capacitor E1, a capacitor terminal JP1 and a capacitor reverse connection protection circuit, wherein E1 is a polar electrolytic capacitor which is protected and used for being connected to other circuits, JP1 is provided with two terminals, and the anode and the cathode of E1 are connected with the two terminals of JP1, and the protection circuit is characterized in that the capacitor reverse connection protection circuit consists of field effect tubes Q1, 555 timer, a relay JDQ, a light emitting diode L ED, a voltage stabilizing diode D1 and a direct current power supply circuit, the field effect tube Q1 is an N-channel enhanced type, the anode of E1 is connected with JP1 through the normally open point of the relay JDQ, the grid of the field effect tube Q1 is connected with the anode of E1, the grid of the Q1 is connected with the source of the field effect tube Q2, the source of the Q1 is connected with the power ground, the drain of the Q1 is connected with the power supply through a resistor R3 and a light emitting diode L, the anode of the JDQ 555 timer, the trigger terminal is connected with the power supply terminal, the trigger terminal of the timer, the positive resistor R595, the trigger terminal is connected with the power supply terminal of the positive resistor, the positive resistor R8653 and the trigger terminal of the timing resistor, the reset terminal of the timing resistor, the timing resistor JDQ1, the reset terminal is.

The invention relates to a protection circuit for realizing the reverse connection of a polar electrolytic capacitor by using a 555 timer, wherein a direct current power supply circuit is composed of a transformer TB, a three-terminal voltage regulator tube PV, an electrolytic capacitor E3, an electrolytic capacitor E2 and a full-bridge rectification circuit consisting of diodes D3, D4, D5 and D6, the primary side of the transformer is connected to an alternating current commercial power, the secondary side of the transformer is connected to the input end of the full-bridge rectification circuit, the anode of the output end of the full-bridge rectification circuit is connected to the input end of the three-terminal voltage regulator tube PV, and the output end of the three-terminal voltage; the electrolytic capacitor E3 is connected with the output end of the full-bridge rectification circuit, and the electrolytic capacitor E2 is connected with the output end of the three-terminal voltage regulator tube PV.

The invention relates to a protection circuit for realizing the reverse connection of a polar electrolytic capacitor by using a 555 timer, wherein two ends of a JDQ coil of a relay are connected in parallel with a diode D2 playing a role of freewheeling, the anode of a D2 is connected with the output end of the 555 timer, and the cathode of a D2 is connected with the positive end of a power supply.

The invention discloses a protection circuit for realizing reverse connection of a polar electrolytic capacitor by using a 555 timer, wherein the resistance values of a resistor R1 and a resistor R2 are both 10k omega, the resistance value of a resistor R3 is 4.7k omega, and the resistance value of a resistor R4 is 100k omega.

The protection circuit has the advantages that the protection circuit with the reversely connected polar electrolytic capacitor comprises the polar electrolytic capacitor E1, a field effect transistor Q1, a 555 timer, a relay JDQ, a light emitting diode L ED and a capacitor terminal JP1, the electrolytic capacitor E1 is connected to JP1 through the normally open point of the relay JDQ, the relay JDQ is arranged at the output end of the 555 timer, the light emitting diode L ED is arranged on the drain electrode of the Q1, when the JP1 is not connected into other experimental circuits or when the experimental circuits are connected into other experimental circuits but are not electrified, the grid of the Q1 is free of voltage, the Q1 cut-off L ED is not lightened, the 555 timer outputs a high level, the relay JDQ coil is not electrified, the normally open point of the relay JDQ is kept in an off state, the electrolytic capacitor E1 is not connected into the experimental circuit, when the E1 is connected into the experimental circuits reversely (incorrectly), the voltage stabilizing diode is conducted to pull the 2 pin of the 555 timer to a low level, the timing pin is pulled to a low level, the timing pin JDQ 466 pin is connected into the experimental circuit, the high timing coil, the experimental circuit is not connected to the experimental circuit, when the timing pin 46Q 465 is connected into the experimental circuit, the high timing pin is connected to a timing pin of the experimental circuit, the timing diode is not connected to a timing pin 465, and the timing pin is connected to the timing diode 46Q 465, when the timing circuit, the timing pin is connected to the high timing pin of the timing.

Therefore, when the polar electrolytic capacitor E1 is mistakenly connected to the experimental circuit, the protective circuit can keep the capacitor E1 in a disconnected state all the time, so that the polar electrolytic capacitor E1 is effectively protected, the light-emitting diode L ED is lightened to warn of a wiring error, and the phenomena of capacitor damage and capacitor explosion caused by the wiring error of the polar electrolytic capacitor in the experimental process of students are avoided.

Drawings

FIG. 1 is a circuit diagram of a protection circuit for reverse connection of a polar electrolytic capacitor with a 555 timer according to the present invention.

In the figure, 1 is provided with a polar electrolytic capacitor E1, 2 is provided with a field effect transistor Q1, 3 is provided with a 555 timer, 4 is provided with a relay JDQ, 5 is provided with a light emitting diode L ED, 6 is provided with a capacitor terminal JP1, 7 is provided with a transformer TB, and 8 is provided with a three-terminal regulator tube PV.

Detailed Description

The invention is further described with reference to the following figures and examples.

As shown in FIG. 1, a circuit diagram of a protection circuit for realizing reverse connection of a polar electrolytic capacitor by using a 555 timer of the invention is provided, which comprises a polar electrolytic capacitor E1 (1), a capacitor terminal JP1 (6) and a reverse capacitor protection circuit, wherein E1 is the protected polar electrolytic capacitor and is used for connecting into other experimental circuits, the capacitor terminal JP1 is composed of two terminals, the anode of the polar electrolytic capacitor E1 is connected with one terminal of JP1 through the normally open point of a relay JDQ, and the cathode of E1 is connected with the other terminal of JP 45, the reverse capacitor protection circuit is composed of a field effect tube Q1, a 555 timer (3), a relay JDQ (4), a light emitting diode L ED and a DC power supply circuit, the DC power supply circuit is used for providing stable DC voltage, the power supply is just Vcc, and the power supply is GND.

The field effect transistor Q1 is shown as an N-channel enhancement type, the grid of the field effect transistor Q1 is connected with the cathode of a polar electrolytic capacitor E1, the grid of the Q1 is connected with the source of the Q1 through a resistor R2, the source of the Q1 is connected with the power ground, the emitter of the Q1 is connected with the positive end of a power supply through a series circuit formed by a resistor R3 and a light emitting diode L ED (5), R2 provides a current path for the source grid of the MOS transistor, the field effect transistor Q1 is used for controlling and driving the light emitting diode L ED to be turned on, and the light emitting diode L ED is used for indicating whether the polar electrolytic capacitor E1 is reversely connected.

The 555 timer is an integrated circuit chip, and the model of the adopted chip is NE 555; the trigger end (the pin marked with 2) of the 555 timer 3 is in short circuit with the threshold end (the pin marked with 6), the trigger end is in short circuit with the threshold end and then is sequentially connected with the anode of E1 through the normally open points of resistors R1 and JDQ1, and the trigger end and the threshold end of the 555 timer 3 are grounded through a resistor R4. Resistor R1 plays two roles, one is to transmit the signal of JP1 for correct wiring, and the other is to limit the current. Resistor R4 is used to pull pin 2 and pin 6 of 555 timer 3 to ground when JP1 is not connected or when the experimental circuit is not powered although JP1 is connected to other experimental circuits.

The power supply end (pin marked with 8) and the reset end (pin marked with 4) of the 555 timer 3 are both connected to a positive power supply Vcc, the control end (pin marked with 5) and the discharge end (pin marked with 7) of the 555 timer 3 are both suspended, and the ground end (pin marked with 1) of the 555 timer is connected to a power supply ground GND. The output end of the 555 timer 3 is connected with a coil of the relay JDQ in series and then connected to a positive power supply Vcc. When the output Vo of the 555 timer 3 outputs a low level, a loop where a coil of the relay JDQ is located is electrified, a normally open point of the relay JDQ is closed, and a polar electrolytic capacitor E1 which can be closed after the normally open point of the JDQ is closed is put into the connected experimental circuit. After the coil end point of relay JDQ, in order to avoid its both ends to produce too high induced voltage, the both ends of relay JDQ coil still are parallelly connected with diode D2, and the positive pole of D2 connects in 555 timer's output, and the negative pole of D2 connects directly on the power to realize the afterflow after the relay JDQ coil outage.

The direct-current power supply circuit is composed of a transformer TB (7), a three-terminal voltage regulator tube PV (8), an electrolytic capacitor E3, an electrolytic capacitor E2 and a full-bridge rectification circuit composed of diodes D3, D4, D5 and D6, wherein the primary side of the transformer is connected to an alternating-current mains supply, the secondary side of the transformer is connected to the input end of the full-bridge rectification circuit, the anode of the output end of the full-bridge rectification circuit is connected to the input end of the three-terminal voltage regulator tube PV (8), the output end of the three-terminal voltage regulator tube PV forms a power supply positive Vcc, and the. The electrolytic capacitor E3 is connected with the output end of the full-bridge rectification circuit, the electrolytic capacitor E2 is connected with the output end of the three-terminal voltage regulator tube PV, and the electrolytic capacitors E3 and E2 realize the functions of filtering and voltage stabilization.

When the transformer TB is connected with a power supply, the circuit starts to work.

When JP1 is not connected to other experimental circuits or is connected to other experimental circuits but the experimental circuits are not electrified, the resistor R4 pulls the pin 2 and the pin 6 of the 555 timer 3 to the ground potential, the potential is 0, the output Vo of the 555 timer 3 outputs high level, the coil of the relay JDQ is not electrified, the relay JDQ does not act, and the polar electrolytic capacitor E1 is not connected to the experimental circuits, at the moment, as no current exists on the resistor R2, the field effect transistor Q1 is not conducted, and the error indicator lamp L ED is not lighted.

When E1 is incorrectly connected in an experiment and the experimental circuit is powered on, namely the voltage of a capacitor terminal JP1 is positive and negative, a voltage is formed on a resistor R2, a field effect transistor Q1 is in saturated conduction, and an error indicator lamp L ED emits light to indicate that the connection of E1 is wrong at the moment, the voltage of the positive electrode of a voltage stabilizing diode D1 is higher than the voltage of the negative electrode of the voltage stabilizing diode D3583 at the moment, D1 is conducted, pin 2 and pin 6 of a 555 timer 3 are pulled to the ground potential by a diode D1, so that the output Vo of the 555 timer outputs a high level, a relay JDQ does not act, and E1 is not connected into the experimental circuit.

When the JP1 is connected correctly in the experimental circuit and the experimental circuit is powered on, the upper part and the lower part of a capacitor terminal JP1 are negative, the pin 2 and the pin 6 of the 555 timer 3 are high in potential, the output end Vo of the 555 timer 3 outputs low level, the coil of the relay JDQ is powered on, the normally open point of the relay JDQ is closed, and the polarized electrolytic capacitor E1 is connected into the experimental circuit, at the moment, the grid source electrode of the field effect transistor Q1 bears reverse voltage, so that the Q1 is cut off, and the error indicator lamp L ED does not emit light.