JPS5917010Y2 - display circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display circuit that can display whether the power is turned on or not, and whether the device is in an operable state.

For example, in a tape recorder with a remote terminal, the motor circuit is connected in series to the remote terminal, and when a remote plug is inserted into the remote terminal, the motor circuit is energized only by turning on and off the remote switch connected to the remote plug. Or there is a power outage and tape running is being controlled.

Therefore, when the remote plug is inserted into the remote terminal, even if the record button on the tape recorder is pressed, if the remote switch is off, the tape will not run and the user may not notice that no recording is made.

The present invention relates to an effective display circuit that can be used in such a tape recorder, especially when the power switch is off, when the power switch is on, when the remote switch is off, and when both the power switch and the remote switch are on. The present invention provides a display circuit that can display each state.

The present invention will be explained below with reference to the drawings.

In FIG. 1, 1 is a magnetic head, 2 is an amplifier, 3 is a speaker, 4 is a battery, 5 and 6 are first and second switches connected in series to the battery 4, and the second switch 6 is installed on the remote jack. The switch is switched from the on state to the off state by inserting a remote plug (not shown) into the remote jack.

7 is a motor that drives the tape 8; 9 and 10 are first and second transistors forming an unstable multi-by-break circuit; a light emitting diode 11 is connected to the collector side of the first transistor 9; Transistors 9, 10
A parallel circuit 1 including a capacitor 12 and a resistor 13 having a resistance value greater than the winding resistance value of the motor 7 on the emitter side of the motor 7.
4 is connected.

A diode 15 is connected between the emitters of the first and second transistors 9 and 10 and the connection point between the second switch 6 and the motor 7 in a direction opposite to the battery 4.

Next, the operation of the present invention will be explained.

First, when the first switch 5 is turned off, the light emitting diode 11 does not emit light.

Next, the first switch 5 is turned on. At this time, if the second switch 6 is turned on, the motor is energized and the tape 8 can be driven to perform recording or reproduction.

In this state, the diode 15 is reverse biased and turned off, and the first and second transistors 9 and 10 are connected to the resistors 16 to 15.
19. Repeat on/off with a time constant determined by the capacitor 20, 21 and the parallel circuit 14 of the resistor 13 and capacitor 12.

Now, if the first transistor 9 is turned on, the battery 4
Switch 5, light emitting diode 11. First transistor 9
Since a current flows through the collector emitter of
When the transistor 9 is turned off, the light emitting diode 11 is turned off.

By blinking the light emitting diode 11 in this manner, it is indicated that the tape 8 is in the driving state.

By the way, when the remote plug is inserted into the remote jack for remote control, the second switch 6 is turned off.

If the remote switch (not shown) is turned off at this time, the motor 7 will not be energized and the tape 8 will remain stopped.

In this state, the diode 15 is turned on without being reverse biased, so that the resistor 13 is connected to the resistor of the motor 7 in parallel.

Therefore, since the resistance value of the parallel circuit 14 becomes small, the on/off speeds of the first and second transistors 9 and 10 become faster.

Also, a light emitting diode 11. The current flowing through the collector emitter of the first transistor 9 and the resistive bone of the parallel circuit 14 increases.

Therefore, the blinking speed and brightness of the light emitting diode 11 are brighter than before, and the first switch 5 is turned on.
It can be clearly seen that the second switch 6 is turned off.

When the remote switch is turned on in this state, the motor 7 is energized via the remote switch, so the tape 8
can run and play or record.

At this time, the diode 15 is turned off as described above, so the first and second transistors 9 and 10 are turned on and off slowly, and the light emitting diode 11 is also turned on and off slowly.

FIG. 2 shows another embodiment of the present invention, in which a transistor 22 is added so that it is turned on only when the second switch f6 is turned off, and at that time, through the transistor 22, a signal with a relatively high resistance is connected. By connecting a small resistor 23 through the resistor 13, the same operation as above is performed.

FIG. 3 shows yet another embodiment of the present invention, in which, contrary to the above, when the second switch 6 is on, the transistor 24 is turned on, reducing the time constant of the parallel circuit 14, and reducing the time constant of the parallel circuit 14. The switching speed of the second transistors 9 and 10 is increased, and when the second switch 6 is turned off, the time constant of the parallel circuit 14 is increased to slow down the switching speed of the first and second transistors 9 and 10.

As mentioned above, in the display circuit of the present invention, when the main power switch is turned on, the display element flashes, so it can be confirmed at a glance that the power switch is turned on, and it can also be used to turn on/off switches for remote control, etc. Since the blinking period and brightness of the display element can be changed,
The operating state at that time can be clearly determined, which is convenient in practice.

[Brief explanation of drawings]

FIG. 1 is a display circuit diagram of the present invention, and FIGS. 2 and 3 are circuit diagrams showing other embodiments of the present invention. 4... Battery, 5... First switch, 6... Second switch, 7... Motor, 9... First transistor,
10... Second transistor, 11... Light emitting diode, 12... Capacitor, 13... Resistor, 14...
・Parallel circuit, 15...diode.

Claims (1)

[Scope of utility model registration request] A parallel circuit of first and second transistors forming an unstable multivibrator, a display element connected to the collector side of the first transistor, and a resistor and a capacitor connected to the emitter side of the first and second transistors. a first switch connected between the power supply and the first and second transistors; a second switch connected between the first switch and the tape drive motor; A display circuit comprising a switching element that is turned on and off to change the time constant and impedance of the parallel circuit.