DE2005853A1 - Circuit for switching a load on and off - Google Patents

Description

STEN-AKE OLAUS RYDBORN ,
Kvarngatan 7, 3 ^ 3 00 ÄLMHULT ,

(Sweden)

CIRCUIT TO SWITCH ON AND OFF A LOAD

The invention relates to a circuit for switching on and off a load that is connected to a switching circuit via a Power source is connected and consists of one lamp or several lamps connected in parallel. Such a circuit is special, but not exclusively suitable as a so-called automatic staircase timer, which is used for timed ignition of mostly multiple light sources (lightbulbs) are used in general spaces that only provide temporary lighting, for example for through traffic.

All previously known automatic staircase time switches are of the electromechanical type and have associated therewith Inconveniences and disadvantages. One of the main disadvantages of known staircase timers is that they have to be switched on can be brought to the load connected to it,

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see whether external conditions make such a switch-on unnecessary do. This means that the well-known staircase time switches allow the light sources to be lit even when when the prevailing lighting conditions are completely sufficient.

These inconveniences are eliminated in the circuit specified at the beginning by the invention by the switching circuit is connected to a manually operable switch-on circuit and a blocking circuit, which according to a predetermined Ambient light intensity blocking the actuation of the switch circuit by means of the manually operable switch-on circuit, and by the switching circuit is connected to a switch-off or extinguishing circuit, which reduces the load after a predetermined switch-on period turns off automatically.

The invention will be described in more detail below with reference to the drawing.

It shows:

1 shows a circuit diagram of a circuit according to the invention, and

FIG. 2 is a circuit diagram of another embodiment of FIG circuit according to the invention.

The circuit shown in Fig. 1 has a pair of input terminals A and B, one of which is also an output terminal or B. serves as a neutral connection, as well as a pair of output terminals C, D. A power source with a. Voltage of preferably 220 V and a frequency of 50 Hz coupled. A load is coupled to output terminals B, C,

which in this case a number of lamps L connected in parallel

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Staircase lighting is, of which only one lamp is shown in the drawing. Λ11 the initial lines ^, D is a Manually operated switch circuit coupled, which in this case consists of a number of push-button switches connected in parallel S consists, of which only one switch is shown in the drawing and in each of which a glow lamp G and in series with it a resistor SR are built over the input terminals A and Ii a capacitor C6 is switched on, which serve as interference protection.

The circuit shown in FIG. 1 comprises a section which is used for feeding the electronic sleeper current part the circuit is used and a resistor Rl, a Diode D2, a capacitor Cl, a resistor R2 and a Includes zener diode D3. The resistor Rl is connected between the input terminal L and the diode D2, which has opposite polarity compared to the Widerstana Rl. Of the Capacitor Cl is switched on between the side of diode D2 facing away from resistor Rl and liingangsklemme A. On the side of the diode D2 facing away from the resistor R1, the resistor R2 is also connected, its opposite End coupled to the input end of the Zener diode D3 while the output end of this diode is coupled to input terminal A.

The power circuit for the specified switching on and off of the load or, in the present case, the Ignition and extinction of the lamps L includes a bidirectional Thyristor Dl and a for inn specific control

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circuit with a double base transistor T3. The bidirectional thyristor Dl is between the input terminal A and the output terminal C is switched on and its control electrode is via a resistor Rl7 to the input terminal A and coupled to the control electrode of the double base transistor T3 via a capacitor C5. The double base transistor T3 is to the input terminal A via a resistor Rl6 and to the one

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Output of the feed circuit coupled - thus the double base transistor T3 and the resistor Rl6 are deemed to be switched on via the outputs of the feed circuit, from which outputs one corresponds to the input terminal A and the other to the connection between the diode D3 and the resistor R2. The input terminal A is connected to the control electrode of the double base transistor T3 via a resistor R15 and a resistor Rl8 coupled. Another double base transistor T2 is between the connection between resistors R15 and R18 and the connection coupled between the diode D3 and the resistor R2, while its control electrode is connected to one terminal of a resistor R9 is coupled, the other terminal of which is coupled to a diode D8 connected in parallel to a resistor R8. The diode De has opposite polarity uu; 'compared to resistor R9. the Connection between the diode D8 and the resistor RS is to the input terminal A via a variable resistor; land R13 as well to the connection between the diode D3 and the resistor R2 via a diode D6 and a capacitor C3 connected in series with it coupled. The diode D6 is opposite to the capacitor C3 Polarity and the connection between the diode D6 and the capacitor C3 is via a resistor R7 to the input of a Thyristor D5 coupled. The output of the thyristor D5 is connected to the Connection between the diode D3 and the resistor R2 coupled, while the control electrode of the thyristor D5 is connected to the connection coupled between the diode D3 and the resistor R2 via a resistor Ro 'and to the output of a diode D4 via a resistor R5 is. The connection between resistor R5 and the Diode Di * is connected to the connection between diode D3 and the resistor

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stood R2 coupled via a capacitor C2. The input of the diode Ok is coupled to the connection between the diode D3 and the resistor R2 via a resistor R ¹ J and to the output terminal D via a resistor R3 or the conductor referred to as ignition conductor in lighting contexts.

The circuit described above also has a blocking circuit which comprises a transistor T1 and a resistor network. The collector of the transistor Tl is connected to the input terminal A via a resistor R1 * J, the emitter of the transistor Tl via a capacitor C ¹ J to the connection between the diode D3 and the resistor R2 and the base of the transistor Tl to the sliding contact of a potentiometer RIl coupled via a diode D7, which has opposite polarity to the base of the transistor Tl. The connection between the emitter of the transistor Tl and the capacitor C ¹ I is coupled to the connection between the control electrode of the double base transistor T2 and the resistor R9. The connection between the base of the transistor T1 and the diode D7 is coupled to the side of the resistor R9 facing away from the control electrode of the transistor T2.

In addition to the aforementioned potentiometer RIl, the resistance set includes a resistor RIO and a further resistor R12. The potentiometer RIl and the resistors RIO and R12 are connected in series with one another, and this series circle is' ^ switched on between the input terminal A and the connection between the diode D3 and the resistor R2. The one in this series Included resistor R12 is a light sensitive resistor.

The operation of the circuit described above will now be described in more detail. The one contained in the power circuit

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Double base transistor Τ3 becomes after fulfilling the following conditions specified in more detail work as an oscillator and pulses via the capacitor C5 the bidirectional thyristor Dl release, which thereby becomes conductive and in turn switches on the load L.

When you press the push button switch S, the thyristor D5 via the resistors R3 and R5 and the Diode D4 brought to sin. When the thyristor D5 is triggered the capacitor C3 is discharged through the resistor R7 and a current begins through the resistor Rl3 and the diode D6 to fHessen, whereby the capacitor C3 is recharged will. During the charging of the capacitor C3, the transistor Tl and the double base transistor T2 become evident be non-conductive, whereby a current flows through the resistors R15 and R18, softer an oscillation of the transistor T3 the bidirectional thyristor Dl to ignite and to Switching on the load brings. When the capacitor C3 has been charged to a certain level, it becomes the double base transistor T2 conductive, after which the current flowing through the resistor Rl3 through the resistors R8 and R9 and the Diode ü3 will go. Thus, the transistor Tl is also conductive, creating a new current path across the resistor Rl4 and the Transistor T1 is opened to double base transistor T2. There Both the transistor T1 and the double base transistor T2 are conductive, the current to the resistor Rl8 stops and the double base transistor T3 stops its oscillation and its supply of pulses to the bidirectional thyristor Dl. Thus the load is switched off or the Lar / .pe L

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turned off. The resistor Rl3 and the capacitor C3 v / ground «Üyou specify the period of time where the bidirectional thyristor Dl and

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thus the load are switched on. To ignite the lights or to make the lamps unnecessary if this is not necessary for lighting reasons, the uses light-sensitive resistor R12, which senses the prevailing light intensity and accordingly blocks the transistor Tl or it makes it impossible to make it conductive. This transistor Tl is thus conductive as long as it is not necessary for the lamps L to ignite. The lighting value at which it should be possible to ignite the lamps L is set by means of the potentiometer RIl. Since the resistor R13 is variable, the ignition or switch-on period can also be changed.

In Fig. 2, a further embodiment of the invention is illustrated. This embodiment basically agrees with the embodiment described with reference to FIG. 1 both in terms of construction and mode of operation. Furthermore, identical components in the two figures have the same reference symbols. It should be noted, however, that the component values may differ slightly from each other. In the embodiment according to FIG. 2, the diode D4 has been omitted and the resistor Rk in FIG. 1 has been replaced by a capacitor C7, which feeds alternating voltage to a glow lamp G when the pushbutton is not held down. Furthermore, the diode d6 in Fig. 1 has been replaced by a transistor T4, which serves to make the charging of the capacitor C3 as linear as possible, whereby this capacitor can be made smaller and a. less leakage current is obtained in this capacitor, resulting in a cost saving. A resistor R26 is also connected between the variable resistor R13 and the input terminal A

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switched. Certain changes have also been made in the blocking circle. The light-sensitive resistor R12 has been connected in parallel to a resistor R27 so that this resistor is better adapted to the circuit. In addition, the resistors RIl and RIO have swapped their places. Another change in the blocking circuit is that the collector of the transistor Tl is coupled to the base of the transistor T ¹ J and to the side of the diode D2 facing away from the resistor Rl via a resistor R25.

α The biggest difference between the two embodiments can be found in the switching circuit. The only ones left behind Components are the resistors R15 and Rl8. The connection between the resistor RI5 and the resistor Rl8 is to the Control electrode of a double base transistor Pl of the programmable type coupled, the collector of the double base transistor Pl to the emitter of the transistor Tl and the emitter of the double base transistor Pl to the end of the remote from the resistor Rl Diode D2 is connected. The switching circuit also includes two complementarily connected transistors T5 and T6, the emitters of which are on

^ P the end of the resistor R18 facing away from the resistor R15 is switched which end of the resistor is also coupled to the base of another transistor T7. The base of the transistor T5 is coupled to the emitter of the double base transistor Pl via a resistor R19, while the emitter of each transistor TJ, Τ6 and T7 are coupled directly to the emitter of the double base transistor Pl. Furthermore, the base of the transistor T5 and the base of the transistor T6 is coupled to the output terminal B via a resistor R20 or R22. The base of the transistor T6 is on whose collector is coupled via a resistor R21. The collector

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of transistor 'i'7 is connected to the control electrode of the cloppelt-directed Thyristor Dl coupled via a resistor R23.

As already mentioned, the mode of operation of the circuit illustrated in FIG. 2 is basically correct iv.it der the circuit shown in Fig. 1 correspond. For a more detailed explanation, however, the mode of operation is illustrated in FIG. 2 Circuit will be described below. Triple capacitor C2 serves as an interference filter and prevents ignition of the thyristor D5 by transient currents through the resistances R3 and R5. The ignition pulse from push button S flows over the Resistors R3 and R5 to the control electrode of the thyristor D5, whereby this thyristor is triggered. Lei of ignition the thyristor D5 is discharged through the resistor R7 and the capacitor C3 through the resistors R26, R13 and the Short-circuit transistor T4 to minus current. This means that there is no voltage drop across resistor R9, which is why the transistor Tl also becomes non-conductive, which means that the double base transistor Pl is also non-conductive will. Thus, the control electrode of the transistor P1 is also non-conductive, which is why the voltage from the resistor Rl5 go through resistor R18 and transistor T7 will lock. The bidirectional diode Dl is thus ignited and the load is switched on. ! laugh recharging of the capacitor C3, which takes place via the resistors R26 and Rl3, the transistor T4 is the double base transistor Pl make non-conductive. As a result, a current occurs through the resistors RS and R9, which causes a voltage drop

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causes the resistor R9 and makes the transistor Tl conductive. This causes a current through the resistor Rl4 and

the transistor Tl to the collector of the double base transistor. , Pl flow. Oa the collector of this transistor conducts',

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will also conduct its control electrode, whereby the voltage across the resistors Rl5 and Rl8 is short-circuited to minus. The base of the transistor T7 receives no control current and no pulses are fed to the thyristor Dl, which is why the load is switched off. Similar to the circuit shown in FIG. 1, the light-sensitive resistor R12 produces a certain current when it is exposed to light of a certain predetermined strength. This current flows through parts of the resistor RIl and the diode D7 and will thus keep the transistor Tl conductive. Even if the push button S is depressed, which leads to the triggering of the thyristor D5 and the discharge of the capacitor C3, the double base transistor Pl is not de-energized because the transistor Tl is conductive. Thus, the control electrode of the transistor Pl will not become non-conductive, which is why the voltage across the resistor Rl5 is not short-circuited to minus, and the load remains switched off. When the push button S is released, the capacitor C3 is charged again, after which the charging current takes over the cold current to the transistor P1 again, while the load remains switched off. Should the light intensity fall below a certain predetermined value, the transistor T1 will not receive a sufficient current when the capacitor C3 is discharged, as a result of which the transistor P1 ceases to conduct and the load is switched on.

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Claims (1)

PATENT CLAIMS Circuit for switching a load on and off that is connected to a power source via a switching circuit and consists of one lamp or several lamps connected in parallel, characterized in that the switching circuit (Dl, T2, T3, Pl, T5, T6, T7) is connected to a manually operated switch-on circuit (S, D5) and a blocking circuit (Tl, R12) which according to a predetermined ambient light intensity, the actuation of the switch circuit (Dl, T2, T3, Pl, T5, T6, T7) by means of of the manually operated switch-on circuit blocked, and that the switch circuit with a switch-off or extinguishing circuit (ΤΙ, C3, R13) is connected, which automatically switches off the load (L) after a predetermined switch-on period. 2. Circuit according to claim 1, characterized in that the switching circuit has a first operating as an oscillator Double base transistor (T3), a bidirectional thyristor (Dl), whose control electrode is connected to the via a capacitor (C5) Control electrode of the double base transistor (T3) is connected, and a second double base transistor (T2) contains which, if it is made non-conductive, the thyristor (Dl) to switch on the Load (L) brings. 3. A circuit according to claim 1, characterized in that the manually operable Einschaltekreis a switch ^(S); ₍ preferably a push button switch and a thyristor (D5), the control electrode of which is connected to a circuit that can be closed by the switch (SJ). ¹ J. Circuit according to Claim 1, characterized in that the blocking circuit contains a transistor (Tl) which, 009837/1386 BAD ORiGINAL if it is non-conductive, the load (L) across the switch circuit (Dl, T2, T3, Pl, T5, T6, T7) allowed to be switched on. 5. A circuit according to claim ¹ J, characterized in that the base of the transistor (Tl) is connected to a resistor network (RIO, RIl, R12) which determines the voltage at which the transistor (Tl) is made non-conductive, and that a potentiometer (RIl), the sliding contact of which is coupled to the base of the transistor (Tl), and contains a light-sensitive resistor (R12). 6. A circuit according to claim 1, characterized in that the switching circuit has a bidirectional thyristor (Dl), a double base transistor (P1) of the programmable type, a complementary transistor pair (T5, T6) and another transistor (T7) contains, the collector of the double base transistor (Pl) to the blocking circuit (Tl, R12) and the control electrode this double base transistor (Pl) to the emitters of the complementary transistors and the base of the further transistor a resistor (Rl8) is connected and wherein the collector of the further transistor (T7) to the control electrode of the bidirectional Thyristor (Dl) is connected, 7. A circuit according to claim 2, characterized in that a capacitor (C3) during charging the transistor (Tl) and the second double base transistor (T2) keeps non-conductive, whereby the double-directional thyristor (Dl) during charging of the capacitor (C3) will keep the load (L) switched on. 009837/1366