DE2038111A1 - Circuit arrangement of a tone signal generator - Google Patents

Description

W 1623

Tokyo Tokei Seizo Kaisha, Limited

Japan

Circuit arrangement of a tone signal generator

The invention relates to the circuit arrangement of a two-stage tone signal generator which has a switch can be connected to a power source.

There are alarm signal generators known from the beginning Generate a constant alarm signal until the end. Furthermore, two-stage tone signal generators have recently been used develops, which initially emits a low-frequency tone for a predetermined period of time, a relatively low ringing tone or an intermittent one Generate a ringing signal before they then emit a loud or higher-frequency ringing signal of the same type. ™ The previously known two-stage tone signal generators of this type essentially use mechanical devices and are therefore relatively complex, expensive to manufacture and quite prone to failure.

Having developed electrical clocks in recent times who use electrical energy to drive, it is to achieve small and simply constructed Clocks desirable, also the sound signal of such a clock equipped with an alarm clock purely electrically

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produce. A similar problem arises with numerous other tone signal generators.

The invention consists essentially in the fact that a time circuit is provided which has a charging circuit and, contains a transistor in whose bias circuit a capacitor of the charging circuit is arranged, that further an astatic multivibrator and an amplifier is provided, which the amplified multivibrator output signal supplies an electrical tone signal generator forming the load on the amplifier, and that. still the time cycle, the astatic multivibrator and the amplifier can be connected in parallel to the power source and the load resistance of the time circuit and the bias resistance of the multivibrator can be formed by a single, common resistor.

Such a circuit arrangement initially generates an intermittent one during a predetermined initial period Sound signal, which then changes into a continuous signal. During each loading period of the timing circuit the oscillator pulses of the astatic multivibrator are amplified and the electrical tone signal generator fed, which forms the load of the amplifier; so during this period there will be an intermittent Sound signal emitted. Is a certain by the charging of the capacitor of the charging circuit of the time circuit When the voltage value is reached, the transistor, in whose bias circuit this capacitor is located, becomes conductive, see above that a current flows through the load resistance of the transistor. Since this load resistance also forms the bias resistance of the astatic multivibrator the oscillation of the multivibrator is interrupted, after which a current flows directly through the load of the amplifier

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and produces a continuous tone. So it happens a two-stage sound signal generation, whereby by setting the time constants of the multivibrator and the charging circuit both the time interval of the intermittent tone and the total duration of the intermittent tone generation can be set.

The circuit of FIG. 1 includes a timing circuit (which makes use of a charging circuit), an astatic multivibrator 2 and an amplifier 3 with one the load on the circuit forming electrical tone generator Ζ, for example a bell or a Buzzer.

The circuit also includes a switch S, which is operated, for example, by an alarm spring, and a power source E. The timing circuit 1 contains a charging capacitor C, a charging resistor PL and an npn or pnp transistor ^. The multivibrator 2 includes a gate resistor Rp, charging resistors R, and R _1. , Capacitors C and resistors r for setting the time constant of the multivibrator and pnp (or npn) transistors Tr and Tr _7,. The amplifier 3 contains a pnp (or npn) transistor Tr ^. as well as a pre-tensioning resistor

stood Rr-.
5

The timing circuit 1 and the multivibrator 2 are connected together via the resistor R "; the multivibrator 2 is connected directly to the amplifier 3 (containing the tone generator Z); both are parallel to the power source E.

If one now assumes that the one in the internal mechanism is a Clock arranged switch S has been closed, the current source E is thereby simultaneously to the charging circuit in time circuit 1, to the astatic multivibrator 2

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and the amplifier

serves in two ways as load resistance of \ Tr ₁ in time circuit 1 and as series resistance for astatic multivibrator 2; it is also common to both circles and thus creates a gate effect »

Simultaneously with the closing of the switch S, the multivibrator 2 is connected to the power source E via the resistor R ^; As a result, a square-wave voltage is generated at the resistor R ^, which depends on the time constant determined by the capacitor C and the resistor r. This square wave voltage is generated by the transistor Tr ₁ . of the amplifier 3 amplified. The output circuit of the amplifier, ie the tone generator Z, is thus traversed by an intermittent current. The period of this intermittent current can be chosen arbitrarily by choosing the time constants by means of the capacitor C and the resistor r. Simultaneously with the closing of the switch S, on the other hand, electrical charge storage begins in the capacitor C via the resistor R ₁ , the potential difference between the base and the emitter of the transistor Tr ₁ increasing according to the time constants given by the capacitor C and the resistor R _1. If this potential difference reaches a predetermined value, the transistor Tr ₁ becomes conductive, so that a current flows through the load resistor R ₂ . This results in a sudden voltage drop across this resistor Rp. Since the resistor R _{2 is also connected} as a series resistor to the astatic multivibrator 2, a bias voltage is suddenly applied to the astatic multivibrator 2 in this way, which then stops oscillating.

As soon as the astatic multivibrator 2 no longer oscillates, the load resistance R ₁ ^ of this oscillator acts

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even as the bias resistor of the transistor Tr ^ in the amplifier 3. Its base potential is reduced as a result, so that a constant, uninterrupted Current flows through the tone generator Z, as a result continues to ring or hum.

This mode of operation over time will be explained in more detail with reference to FIG. 2: The period T ^ is determined by the time constant which is dependent on the capacitor C and the resistance r of the astatic multivibrator. The arbitrarily adjustable period T «, which ends at the beginning of the continuous tone, is determined by the capacitor C and the resistor R _{1 of} the time circuit. During the period T i, the continuous tone is generated. It ends when you open switch S.

The two-stage alarm tone generator according to the invention thus consists of a very simple electrical circuit; their manufacture is therefore simple and the Reliable operation.

The invention is of course not restricted a tone generator for generating a two-stage alarm signal; Rather, it can also be used to generate son- I

stiger signals, for example from call or warning signals to be used.

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Claims (1)

Claim Circuit arrangement of a two-stage tone signal generator which can be connected to a current source via a switch, characterized in that a timing circuit (1) is provided which contains a charging circuit (C, R ^) and a transistor (Tr.), In whose bias circuit a .Capacitor (C) of the charging circuit is arranged, that an astatic multivibrator (2) and an amplifier (3) is provided, which supplies the amplified multivibrator output signal to an electrical tone signal generator (Z) forming the load on the amplifier, and that the Time circuit (1), the astatic multivibrator (2) and the amplifier (3) can be connected in parallel to the power source (E) and the load resistance of the time circuit (1) and the bias resistance of the multivibrator (2) by a single, common resistor (R ₂ ) are formed. 109852/1643