JPH0222819Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention provides a function (hereinafter referred to as an automatic stop function) that prevents power from being supplied to the tape drive motor control circuit by detecting the stoppage of rotation of the reel stand. This invention relates to a tape recorder having a function (hereinafter referred to as voice operation) of controlling the rotation of a motor according to the level of an input signal.

Conventional configuration and its problems In recent years, most tape recorders have an automatic stop function at the end of the tape in order to eliminate wasteful current supply after the tape has been wound.
Additionally, voice operation functions have come into widespread use in order to eliminate the hassle of repeating recording operations depending on the presence or absence of a signal to be recorded.

A conventional tape recorder will be explained below.

FIG. 1 shows a conventional tape recorder circuit, in which 1 is a voice detection microphone, 2 is an amplifier circuit, 3 is a motor control circuit, 4 is an automatic stop circuit,
24 is a rotary switch whose contacts are intermittently opened and closed by the rotation of the reel stand, 5 and 6 are DC blocking capacitors, 7 and 8 are electrolytic capacitors, 9 is an on/off switch, 10, 11, 12, 13, 14, 15,1
6, 17 are transistors, 18, 19, 20, 2
1, 22, and 23 are resistors. 25 is a voice operation circuit.

First, when the microphone 1 detects a voice, its output is amplified by the amplifier circuit 2. When the switch 9 is open, the transistor 10 is turned on if the output of the amplifier circuit 2 is at a certain level or higher. At this time, the charge accumulated in the electrolytic capacitor 8 is discharged, the base voltage of the transistor 11 drops, and the transistor 11 is turned off, and the transistors 12 and 17 are turned on, and the automatic stop circuit 4 and motor control circuit 3 are turned off. Power is supplied. When switch 9 is closed, transistor 11 is always turned off regardless of the output level of amplifier circuit 2, transistors 12 and 17 are turned on, power is supplied to automatic stop circuit 4 and motor control circuit 3, and voice operation is performed. Yon circuit 25 does not operate.

On the other hand, in the automatic stop circuit 4, when the reel stand is rotating, the rotation switch 24 repeatedly opens and closes, generates pulses, and turns on the transistor 13 intermittently.
Repeat off. At this time, the charge accumulated in the electrolytic capacitor 7 does not reach a level that turns on the transistor 14, and the transistors 15 and 16 turn on, continuing to apply voltage to the motor control circuit 3, and the rotation of the motor does not stop. However, when the tape reaches the end and the reel stand stops rotating, the transistor 13 is always turned off, charge is accumulated in the electrolytic capacitor 7, turns on the transistor 14, turns off the transistors 15 and 16, and the motor control circuit 3 No voltage is applied and the motor stops.

However, the conventional configuration described above requires a very large number of parts to construct the circuit, making it difficult to downsize and reduce the cost of the tape recorder.

Purpose of the invention This invention solves the above-mentioned conventional problems.
The purpose of this invention is to provide a compact, low-cost tape recorder that can significantly reduce the number of parts.

Composition of the invention The present invention includes a microphone for detecting sound, an amplifier circuit for amplifying the output from the microphone, an AC signal generation circuit for converting the rotation of a reel stand into an intermittent AC signal, and the amplifier circuit. A switching level detection circuit detects the output of the output or the output of the AC signal generation circuit and applies it to the next-stage switching circuit, and the output of this detection circuit performs a switching operation to establish continuity and apply a drive voltage to the motor control circuit. A tape recorder comprising a switching transistor and a switching circuit connected to select the output of the AC signal generation circuit and the output of the amplification circuit and apply it to the switching level detection circuit. When the output of the AC signal generation circuit is applied, the motor drive is controlled depending on the presence or absence of that signal, and when the output of the amplifier circuit is applied to the switching level detection circuit, the motor drive is controlled based on the output level. As a result, the number of parts can be significantly reduced, and the tape recorder can be made smaller, lighter, and less expensive.

DESCRIPTION OF THE EMBODIMENTS FIG. 2 shows a tape recorder circuit according to an embodiment of the present invention.

1 is a voice detection microphone, 2 is an amplifier circuit,
3 is a motor control circuit, which is the same as in the conventional example.

26 is a changeover switch, 26-a, 26-b are fixed contacts of the changeover switch 26, 27 is a rotary switch, 28 is a DC blocking capacitor, 29 is an electrolytic capacitor, 30, 31, 32, 33 are transistors, 34, 35 , 36, 37 are resistances.

First, when the microphone 1 detects a voice, its output is amplified by the amplifier circuit 2. When the movable contact of the changeover switch 26 is connected to the fixed contact 26-a, the transistor 30 is turned on if the output of the amplifier circuit 2 is at a certain level or higher.
Then, the charge accumulated in the electrolytic capacitor 29 is discharged through the transistor 7, the base voltage of the transistor 31 decreases, turning off the transistor 31, and turning on the transistors 32 and 33, supplying voltage to the motor control circuit 3. and drive the motor.

Next, the movable contact of the changeover switch 26 is connected to the fixed contact 2.
When connected to 6-b, rotary switch 2
7, a resistor 37, and a capacitor 28. The transistor 30 is intermittently turned on and off by the output of the AC signal generating circuit. At this time, the charge in the electrolytic capacitor 29 is repeatedly charged and discharged through the transistor 30, the base voltage of the transistor 31 does not rise, the transistor 31 is turned off, and the transistors 32 and 33 are turned on, applying voltage to the motor control circuit 3. Drives the motor, but
When the reel stand stops rotating and the rotation switch 27 no longer generates an AC signal, the transistor 30 is turned off, the transistor 31 is turned on, and the transistors 32 and 33 are turned off, applying voltage to the motor control circuit 3, as in the conventional example. The motor stops rotating.

In this way, according to this embodiment, the number of parts can be significantly reduced by sharing the switching level detection circuit and switching circuit for the voice operation circuit and automatic stop circuit, and by switching the switch depending on the purpose of use of the tape recorder. This makes it possible to realize a tape recorder that is smaller, lighter, and less expensive.

Effects of the Invention As described above, the present invention includes a voice detection microphone, an amplification circuit for amplifying the output from the microphone, an AC signal generation circuit that converts the rotation of the reel stand into an intermittent AC signal, and A switching level detection circuit detects the output of the amplifier circuit or the output of the AC signal generation circuit and applies it to the next-stage switching circuit, and the output of this detection circuit performs a switching operation to establish conduction and supply the drive voltage to the motor control circuit. a switching transistor that applies
By providing a switching circuit that is connected to select the output of the AC signal generation circuit and the output of the amplifier circuit and add it to the switching level detection circuit, the number of parts can be significantly reduced, making it smaller, lighter, and less expensive. This is an inexpensive tape recorder, and its effects are significant.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a conventional tape recorder, Figure 2 is a circuit diagram of a conventional tape recorder.
The figure is a circuit diagram showing an embodiment of the present invention. 1...Microphone, 2...Amplification circuit, 3...
Motor control circuit, 27... Rotation switch, 28...
...DC blocking capacitor, 29... Electrolytic capacitor, 30, 31, 32, 33... Transistor,
34, 35, 36, 37...resistor, 26...changeover switch.

Claims (1)

[Scope of utility model registration request] an audio detection microphone, an amplifier circuit for amplifying the output from the microphone, an AC signal generation circuit for converting the rotation of the reel stand into an intermittent AC signal, and an output of the amplifier circuit or the AC signal generation circuit. a switching level detection circuit that detects the output and applies it to the next-stage switching circuit; a switching transistor that performs a switching operation based on the output of the switching level detection circuit to become conductive and apply a drive voltage to the motor control circuit; a switching circuit connected to select the output of the AC signal generation circuit and the output of the amplifier circuit and apply it to the switching level detection circuit;
When the output of the AC signal generation circuit is applied to the switching level detection circuit, it operates as an automatic stop circuit for a tape recorder that controls the drive of the motor depending on the presence or absence of that signal, and also applies the output of the amplifier circuit to the switching level detection circuit. 1. A tape recorder that operates as a circuit that controls the drive of a motor depending on the output level when a motor is applied.