JP2002109901A - Flashlight having electroluminescent diode as light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flashlight with small size, light weight, and improved portability, using an electroluminescent diode instead of a small light bulb as a light source, which prolong the time of use by saving power. SOLUTION: A cell voltage is boosted up to a voltage suitable for an operation of the electroluminescent diode by a transistor circuit with a transformer coupling, and taking a luminous property of electroluminescent diode and a simplification of the circuit into consideration, it is used as a power source of the flash light with alternating current wave form.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flashlight using a light emitting diode as a light source and a transformer-coupled transistor oscillation circuit using a dry battery as a power source.

[0002]

2. Description of the Related Art Currently used flashlight light sources are:
It uses a miniature bulb and heats and emits light from a filament wound in a coil, and requires a considerable amount of current.

[0003]

SUMMARY OF THE INVENTION The present invention uses a light emitting diode as a light source of a flashlight to reduce power consumption, and at the same time, contributes to improvement of portability by downsizing and weight reduction.

[0004]

[Means for Solving the Problems] Unlike miniature light bulbs, the working voltage of which has been set since the time of production, the voltage of the light emitting diode does not correspond to a dry cell, and in use it is stable at a power supply higher than the specified voltage. Current limiting is performed by connecting a series resistor in series. In the present invention, a transistor oscillation circuit connected by a transformer is used, a necessary AC power is directly obtained from a battery, and the AC power is supplied to a light emitting diode, and a half wave thereof is used for light emission.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a transformer-coupled transistor oscillation circuit using a dry cell 1 as a power supply is employed. That is, in this embodiment, the circuit from the negative electrode side of the dry battery 1 to the collector C and the emitter E of the transistor 2 and further to the secondary coil 3b of the oscillation transformer 3 and the primary coil 3a of the oscillation transformer 3 from the base B of the transistor 2 And the circuit leading to the light emitting diode 4 is connected to the positive electrode side of the dry battery 1.

[0006]

As compared with the majority of flashlights which use miniature bulbs as light sources and use dry cells, the flashlight of the present invention has a low power consumption of the light emitting diode even when the fixed loss due to the transistor oscillation circuit is included. Because of the small number, according to the present invention, the power consumption can be greatly improved overall. In addition, since the light emitting diode has many color lights including white light, the flashlight of the present invention can be utilized according to the application by selecting these.

[0007]

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a flashlight according to an embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dry battery 2 Transistor 3 Oscillation transformer 4 Light emitting diode

Claims (1)

[Claims] 1. A flashlight operating a light emitting diode using a transformer-coupled transistor oscillation circuit powered by a dry cell.