JPS5916337B2 - Tape recorder control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape recorder equipped with a so-called timer standby function that releases the pause state and puts the tape recorder into recording or playback mode when power is supplied by a timer device at a set time. .

The standby state of such a tape recorder is the same state as when a pause operation is performed during recording or playback operation, and when power is supplied by the timer device, the pause state is canceled and recording or playback starts. Each mechanism of the tape recorder is configured to start.

The development of timer devices has been remarkable in recent years, and programmable devices have been developed that can control power supply and cut-off any number of times with a single setting.

In contrast, in a tape recorder, the standby operation described above can only be performed once. In addition, if the power supply is cut off due to a power outage or malfunction of the timer device after the power is supplied by the timer device and recording 5 or playback starts, the tape recorder will stop in that state, so the pinch roller There was a problem with deformation. The present invention has been made in view of the above points, and will be described in detail below with reference to the illustrated embodiments.

In the figure, 1 and 2 are resistors and capacitors connected between the power supply line 3 and the ground, and 4 is a pulse signal generation circuit that performs an inverting operation and outputs a pulse signal when the charging potential of the capacitor 2 reaches a predetermined value. ri, transistor 5
|6, a differentiating circuit 9 consisting of a capacitor T and a resistor 8, and a Zener diode 10 for setting an operating point. Reference numeral 11 indicates a plunger which operates to temporarily stop the tape recorder by its suction operation and, conversely, to release the tape recorder from the pause operation state. This is a driving transistor that operates to drive the flansha 11.

13 is a first control switch that can be switched to a different state i5 between a temporary stop operating state and a non-pause operating state;
The movable terminal 13a is connected to the power supply line 3, and the first time the movable terminal 13a comes into contact with the movable terminal 13a in a paused state;
The q-constant terminal 13b is connected to the collector of the driving transistor 12, and the second fixed terminal 13c, which the movable terminal 13a contacts in the non-pause state, is connected to the connection point A between the resistor 1 and the capacitor 2. It is connected via a resistor 14 having a smaller resistance value.

The delay time due to the resistor 1 and capacitor 2 is several seconds, and the delay time due to the resistor 14 and capacitor 2 is 1
It is set to be several milliseconds. Reference numeral 15 denotes a self-holding circuit composed of transistors 16 and 17, etc. The emitter of the transistor 17 is connected to the power supply line 3 via a diode 18 and a resistor 19, and the collector is connected to the power supply line 3 of the plunger 11 via a diode 20. It is connected to the base of the transistor 16 via a diode 21 and a resistor 22.

A large capacity capacitor 23 is connected between the emitter of the transistor 17 and the ground, and a capacitor 24 is connected between the base of the transistor 16 and the ground to prevent malfunction.
is connected. 25 is a control transistor for controlling the operation of the self-holding circuit 15, the emitter is connected to the emitter of the transistor 18, the collector is connected to the base of the transistor 16 via a resistor 26, and the base is connected to the resistor 27. Power line 3 through
It is connected to the.

A diode 28 connected between the base and emitter of the control transistor 25 serves to prevent the transistor 25 from being destroyed. 29 is a second control switch that is switched in conjunction with the first control switch 13; a movable terminal 29a is connected to the base of the transistor 16;
The first fixed terminal 29b that contacts the movable terminal 29a is grounded, and the second fixed terminal 29c that contacts the movable terminal 29a in the non-pause state is open.

Reference numeral 30 denotes a switch connected between the base of the transistor 16 and ground, which is opened during recording and playback states, and closed during fast forwarding, rewinding, and stopping states.

In such a circuit, resistors 31, 32 and 33 connected in parallel to the capacitors 2, 23 and 24 function to discharge the charges stored in the capacitors.
The present invention is constructed as described above, and its operation will be explained next.

The illustrated state is a standby state, in which the tape recorder is in the recording or playback state, with the pause operation button being operated, and power is not being supplied to the power supply line 3. In this state, when the set time comes, power is supplied from the timer device and the electric motor starts rotating, but since the tape recorder is in a paused state, the magnetic tape is not immediately driven to run. Further, when power is supplied from the timer device, a predetermined voltage is applied to the power supply line 3, so that a charging current flows to the capacitor 2 through the resistor 1. When the charging potential of the capacitor 2 reaches a predetermined value after a predetermined time, that is, several seconds, the Zener diode 10
becomes conductive, and the transistors 5 and 6, which were in a non-conductive state, are reversed to a conductive state. As a result, a pulse signal, which is an output signal from the differentiating circuit, is applied to the base of the driving transistor 12, during which the transistor 12 is inverted to a conductive state and causes the plunger 11 to perform a suction operation. Therefore, the temporary stop state is canceled and the first control switch 13 and the second
When the control switch 29 is switched to the opposite position from that shown, the tape recorder is placed in recording or playback operation. Further, when power is supplied to the power supply line 3 by the timer device, the capacitor 23 is connected to the resistor 19 and the diode 1.
8, transistors 16, 17 and control transistor 25 are all non-conducting. As described above, the recording or playback start operation is carried out by the timer device.Next, the operation when the power supply is cut off by the timer device or due to a power outage or the like in such a state will be explained.

In the recording or reproducing state, the first control switch 13 and the second control switch 29 are on the opposite side from the state shown in the figure, and when the power supply is cut off in this state, the potential of the power supply line 3 drops. As a result, the control transistor 25 is turned on by the discharge current of the capacitor 23, and the transistor 1 constituting the self-holding circuit 1-5 is accordingly turned on.
6 and 17 are inverted to conductive states, but at this time positive feedback is applied from the collector of transistor 17 to the base of transistor 16 via diode 21 and resistor 22, so the inversion operation is instantaneously performed. Then, due to the inversion of the self-holding circuit 1-5, the transistor 17
from the collector of plunger 1 via diode 20.
1, the plunger 11 is caused to perform a suction operation. As a result, the tape recorder is in a paused state, and the first control switch 13 and the second control switch 29 are in the state shown. When the charge stored in the capacitor 23 is discharged, the transistors 16 and 17 and the control transistor 25 of the self-holding circuit 1-5 all return to a non-conducting state. This state is the same as the standby state described above, and when power is supplied again by the timer device, similar operations are performed. When the magnetic tape ends, the tape recorder returns to a stopped state by an automatic stop device included in the tape recorder. Although the standby operation by the timer device is performed as described above, the operation in the normal use state will be explained next.

In this case, the first control switch 13 and the second control switch 2
9 is a second fixed terminal 13c, 29c in a non-pause state;
When the main switch (not shown) is closed and power is supplied in this state, a predetermined voltage is applied to the power line 3, and the capacitor 2 is connected to the first control switch 13 and the resistor 14. charged quickly through.
When the charging potential of the capacitor 2 reaches a predetermined value, the transistors 5 and 6 are turned on as described above, and the pulse signal from the differentiating circuit is transferred to the driving transistor 1.
However, due to the switching of the first control switch 13, power is not supplied to the collector of the transistor 12, so the transistor 12 is not conductive and the plunger 11 does not perform a suction operation. Therefore, not only no unnecessary operation is performed, but also no suction operation noise of the plunger 11 is generated. In addition, if a temporary stop operation is performed immediately after the main switch is closed and power is supplied, the first control switch 13 and the second control switch 2
9 is switched to the state shown in the figure, and power is supplied to the collector of the driving transistor 12, but before this switching occurs, the capacitor 2 is charged and the transistors 5 and 6 are inverted to conductive states. When the movable terminal 13a of the first control switch 13 comes into contact with the first fixed terminal 13b, the pulse signal from the differential circuit disappears, and the plunger 11 is not caused to perform a suction operation. Next, the operation when the power supply is cut off due to a power outage or the like during normal use will be explained.

If the power supply is cut off during recording or playback operation, the plunger 11 is caused to perform a suction operation by the discharge current of the capacitor 23 as described above, and the tape recorder is put into a temporary stop state. Deformation can be prevented. Furthermore, when the power supply is cut off during a pause state in the recording or playback state, the control transistor 25 is reversed to a conductive state as the voltage of the power supply line 3 drops, but the transistor 16 constituting the self-holding circuit 15 is turned on. The base is the second control switch 2
Since the transistor 16 is grounded by 9, the transistor 16 is not turned on. Therefore, self-holding circuit 1
5 is never reversed and the plunger 11 does not perform a suction operation. Therefore, the power to the tape recorder is cut off while the tape recorder remains in a paused state, thereby preventing deformation of the pinch roller or the like. Furthermore, if the power supply is cut off in a state other than recording or playback, that is, in a fast forward or rewind operation state, the switch 30 is closed, so even if the control transistor 25 is reversed to a conductive state, the self-holding circuit 15 is reversed. Without doing so, the plunger 11 does not perform unnecessary suction operations. Furthermore, when the voltage on the power supply line 3 drops slightly due to fluctuations in the power supply voltage, current flows through the control transistor 25, but the capacitor 24 connected between the base of the transistor 16 and the ground absorbs the current, causing the transistor 16 to malfunction. There will be no conduction.

As explained above, the control circuit of the present invention switches the tape recorder from the paused state to the playback or recording operation state by the suction action of the plunger when power is supplied while the function of the tape recorder is in the paused state. If the power is cut off while the device is in the playback or recording mode, the suction action of the plunger causes the playback or recording mode to be switched to the paused mode, so a timer device is used to control the power supply and cutoff. If repeated, the tape recorder can be switched from a paused state to a playback or recording state, and from a playback or recording state to a paused state, and the present invention, when used in conjunction with a programmable timer device, can This is extremely convenient because the recording operation can be performed a set number of times.

In addition, if the power is cut off due to a power outage or opening of the power switch while the tape recorder is in the playback or recording mode, the tape recorder is put into a pause state, which prevents deformation of the pinch rollers, etc. Furthermore, when power is supplied, the plunger is activated after a predetermined period of time to switch from a paused state to a playback or recording state, so that unpleasant sounds are not played or recorded as the motor starts up. , the present invention is most suitable as a control circuit for a tape recorder.

[Brief explanation of drawings]

The illustrated circuit is one embodiment of the control circuit of the present invention. Explanation of main drawing numbers, 3...Power line, Dan...
... Differential circuit, 11 ... Plansher, 12.
... Drive transistor 1, 13 ... First control switch, 1" ... Self-holding circuit, 25.
...Control transistor 29...Second control switch.

Claims (1)

[Claims] 1. In a tape recorder configured to switch to and release the pause state by the suction action of a plunger, when power is supplied while the function of the tape recorder is in the pause state, The subsequent suction action of the plunger releases the paused state and puts the tape recorder into the playback or recording mode, and if the power is cut off while the tape recorder is in the playback or recording mode, the playback or recording mode will start. 1. A control circuit for a tape recorder, characterized in that the plunger is immediately caused to perform a suction operation by the discharged charge of a capacitor that has been charged when the tape recorder is in the state, thereby causing the tape recorder to temporarily stop.