JPS5915165Y2 - tv jiyoung camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a partially battery operated television camera.

Battery partially active television cameras are powered by AC power.
Since there is no need to supply power, it is highly mobile and can be used for outdoor photography and photography in any location, which has great utility value.

However, since batteries have a limited electrical capacity, it is necessary to know when to replace them.

That is, depending on the type of battery, if it is over-discharged, it may become impossible to reuse it.

Therefore, a low battery voltage warning device is required, and a light emitting diode is used as an indicator.

Here, the conventional method will be described using FIGS. 1 and 2.

FIG. 1 is a diagram showing typical discharge characteristics of a battery. The horizontal axis represents time, and the vertical axis represents battery voltage. Voltage E is the minimum level necessary for stabilizing the battery voltage stabilization circuit 14 in FIG. The battery voltage values are shown, 1o-1 is a period in which the battery voltage is almost constant, 11-12 is a period in which the battery voltage gradually decreases, and 12-13 is a period in which the battery voltage is rapidly decreased.

FIG. 2 is a conventional circuit diagram for warning that the battery capacity has decreased below a predetermined value.

1 is battery, 2 is variable resistor, 3, 4.5 is resistor, 6
is a voltage comparator, 7 and 8 are input terminals of the voltage comparator 6, 9 is a reference voltage source, 10 is an output terminal of the voltage comparator 6, 11 is an oscillation circuit, 12 is a light emitting diode, 13 is a switching element, and 14 is a In the battery voltage stabilizing circuit, 15 is a stabilized voltage output terminal, 16 is a load circuit, and 17 is a battery voltage input terminal.

The battery voltage supplied to the battery input terminal 17 is set by the variable resistor 2 so as to be a voltage value slightly higher than the voltage E in FIG. 7.

Further, the other input terminal 8 of the voltage comparator 6 is supplied with a reference voltage from a reference voltage source 9 .

When the voltage value supplied to the input terminal 7 of the voltage comparator 6 is higher than the reference voltage value supplied to the input terminal 8 of the voltage comparator 6, the oscillation circuit 11 is connected to the output terminal 10 of the voltage comparator 6.
A voltage that does not oscillate is output, and switching element 1
3 is in an off state and the light emitting diode 12 does not blink.

Next, when the battery voltage supplied to the battery voltage input terminal 17 decreases to a voltage value slightly higher than the voltage E shown in FIG. is lower than the reference voltage value supplied to the input terminal 8 of the voltage comparator 6, a voltage that causes the oscillation circuit 11 to oscillate is output to the output terminal 10 of the voltage comparator 6, and the switching element 13 is activated at the same period as the oscillation period. The light emitting diode 12 blinks by repeatedly turning on and off, giving a warning that the battery voltage value is approaching the minimum voltage value required for stabilization of the battery voltage stabilizing circuit 14.

However, this alarm circuit has the disadvantage that it requires a large number of elements, complicates the circuit configuration, and cannot display the rate of decrease in battery voltage.

Here, the light emitting diode 12, which is the alarm display means, is installed on the chassis etc. near the cathode ray tube in the eyepiece of the viewfinder, so the alarm may be missed when paying attention to the viewfinder screen. , it is not possible to reliably issue a warning.

The present invention attempts to solve these drawbacks and to ensure the mobility of a partially battery operated television camera.

That is, as shown in FIG.
The above-mentioned problem is solved by using the VBE characteristic to convert the change in I8 in the B area into a direct amount and displaying it on the cathode ray tube of the viewfinder.

FIG. 4 shows an embodiment of the present invention, in which 18 is a battery;
9 is a battery voltage input terminal, 20, 21.22 is a resistor, 23 is a transistor, 24 is a battery voltage stabilization circuit, 25 is a stabilization voltage output terminal, 26 is a load circuit, 27
2 is a display circuit that generates an alarm signal to be displayed on the viewfinder, and 28 is a cathode ray tube of the viewfinder.

t shown in FIG. 1 to the battery input terminal 19.

-41, the emitter-base voltage of the transistor 23 becomes the voltage value in the A region shown in FIG. 3 by arbitrarily selecting the resistors 20 and 21, and the base of the transistor Since no current flows, the collector voltage becomes the ground potential, the display circuit 27 remains in a stopped state, and no alarm display appears on the cathode ray tube 28.

Next, the battery input terminal 19 is connected to the terminal 11-1 shown in FIG.
When a voltage between 2 and 2 is supplied, the base-emitter voltage of the transistor 23 becomes a voltage value in region B shown in FIG.
Since the current flowing through the base of the collector voltage increases, the collector voltage increases, operating the display circuit 27 and displaying the generated alarm display signal on the cathode ray tube 28 as an analog quantity proportional to the increase in the collector voltage.

In addition, 12-1 shown in FIG. 1 is connected to the battery input terminal 19.
When a voltage between 3 and 3 is supplied, the base-emitter voltage of the transistor 23 has a voltage value in region C shown in FIG.

At this time, the collector voltage of the transistor 23 becomes constant, and the operation of the display circuit 27 is maintained so that the generated alarm display signal remains at the maximum level.

In this way, according to this circuit, the rate of decrease in battery voltage can be displayed directly on the cathode ray tube of the viewfinder, and the battery voltage value approaches the minimum voltage value required for stabilization of the battery voltage stabilization circuit 24. You can be alerted to this.

Here, as the display signal from the display circuit 27, appropriate signals such as lines, bars, curtains, points to circles, areas, etc. can be used.

As explained above, according to the present invention, when the battery reaches its minimum operating limit voltage, it is reliably notified on the cathode ray tube that it is time to replace the battery, so that the television camera can be operated with peace of mind. .

[Brief explanation of drawings]

Fig. 1 is a diagram showing the discharge characteristics of a typical battery, Fig. 2 is a conventional circuit diagram for warning of battery voltage decrease, and Fig. 3 is a diagram showing the IBVBE characteristics of the transistor shown in Fig. 4 and changes in collector voltage. FIG. 4 is a circuit diagram showing the alarm circuit of the present invention. 18: Battery, 20, 21.22: Resistor, 23:
Transistor, 24: Battery voltage stabilization circuit, 27
:Display circuit, 28 ni cathode ray tube.

Claims (1)

[Scope of utility model registration request] In a battery-operated partially-operated television camera with a viewfinder, a stabilized battery voltage was applied to the emitter of the transistor to warn of low battery voltage, and the base set the battery voltage as the minimum usable limit. In order to saturate the collector current when the voltage is
is connected to the battery through a resistor and grounded through a second resistor, the collector is grounded through a third resistor, and the voltage of the collector is detected, and the detected voltage is used to reduce the battery capacity. 1. A partly battery-operated television camera, characterized in that the alarm signal is used as a control voltage for a display circuit that generates the alarm signal, and the alarm signal is displayed on a viewfinder at the time of an alarm.