JPH04277479A - Lightning arrester - Google Patents

Abstract

PURPOSE:To construct a lightning arrester in a small size through utilization of patterns of a printed circuit board, and facilitate selection of the setting voltage. CONSTITUTION:One common pattern 10 for electric discharging and a plurality of individual patterns 7, 8, 9 for discharging, which confront the common pattern at varied distance, are furnished one a base board 1 with Cu foils. The individual patterns 7, 8, 9 are connected and disconnected by removable zero-ohm chip resistances 4, 5, 6 with/from a common pattern 3 for changing-over formed alike on the base board with Cu foil. These common patterns 10, 3 for discharging and changing-over are connected with a circuit to be protected.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning arrester used to protect facsimiles and the like.

0002

2. Description of the Related Art FIG. 3 is a diagram showing a conventional lightning arrester of this type. In the figure, 16 is an overvoltage detection element, 17 is a glass case that seals the element 16, and 18 is a lead for mounting on a printed circuit board. It is a line.

Next, the operation will be explained. Lead wire 18
The main body of the lightning arrester is attached to a printed circuit board, and is connected to a connector for connecting a telephone line via a copper foil pattern on the printed circuit board. First, a surge voltage higher than a preset value is applied from the external telephone line to the overvoltage detection element 16 in the lightning arrester. Next, an electric discharge occurs within the glass case 17, causing an instantaneous short circuit between the lead wires 18. This protects the circuit after the lightning arrester from being applied with overvoltage.

0004

Since the conventional lightning arrester is constructed as described above, it must be mounted on a printed circuit board, and it is necessary to secure a space for the lightning arrester. Further, there were other problems such as the need to replace the lightning arrester for each desired set voltage.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a lightning arrester that can save installation space and that can easily change the set voltage.

[0006]

[Means for Solving the Problems] A lightning arrester according to the present invention includes a common pattern for discharging made of copper foil and a plurality of individual discharging patterns facing the same at different distances on a substrate. The individual pattern for discharging is electrically connected to and separated from the common pattern for switching, which is also formed of copper foil on the above board, by a detachable zero ohm chip resistor, and the common pattern for discharging and the common pattern for switching The common pattern is connected to the circuit to be protected.

[0007]

[Operation] The lightning arrester of this invention is constructed from a copper foil pattern on a printed circuit board, so it does not take up much space.
In addition, the discharge voltage between the patterns is determined by the preset pattern gap (creepage distance).
The set voltage can be switched depending on which individual pattern is connected to the switching common pattern using a chip resistor.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a printed circuit board, 2 is a lead wire connected to a telephone line, 3 is a common switching pattern connected to one pole of the telephone line by lead wire 2, 4, 5
, 6 is a chip resistor with a zero ohm value for switching the detection voltage, 7
8 is the individual pattern for medium voltage that detects low surge voltage, 9 is the individual pattern for high voltage that detects high surge voltage, and 10 is the individual pattern for the other side of the telephone line. The common pattern for discharge is connected to the pole by the lead wire 2, 11 is the exposed part of the pattern where solder is applied without applying the solder resist on the pattern, and 12 is the input circuit connected after this arrester. This is the pattern.

Next, the operation will be explained. First, a surge voltage from the telephone line is transmitted to the switching common pattern 3 on the printed circuit board 1 via the lead wire 2. Assuming that only the chip resistor 4 for setting the detection voltage is installed, if the transmitted surge voltage is larger than the set detection voltage, the chip resistor 4 will be connected to the low voltage individual pattern 7.
A discharge occurs between the common pattern 10 and the common pattern 10 for instantaneous short-circuiting. In this way, by short-circuiting the two poles of the telephone line, application of surge voltage to the input circuit pattern 12 and beyond is prevented.

Discharge occurs between the exposed portions 11 of the patterns 7 and 10, and the detection voltage is set depending on the distance of this gap. An individual pattern 8 for medium voltage and an individual pattern 9 for high voltage are prepared for setting several different detection voltages, and the switching chip resistors 5 and 6 are appropriately set each time.

In the above embodiment, a lightning protection pattern is provided on one side of the printed circuit board 1.
Lightning protection patterns may be provided on both sides.

FIG. 2 will be explained below. 13 is a double-sided printed circuit board having patterns on both sides, 14 is two patterns connected to a telephone line, and 15 is a through hole passing through the double-sided printed circuit board. Further, in FIG. 2, solid lines indicate the front side pattern, and dotted lines indicate the back side pattern.

The surge voltage transmitted from the telephone line appears at the exposed portion 11 of the through hole 15 via the dotted line pattern 14. If the preset voltage is exceeded, a discharge occurs between the exposed part 11 of the solid line pattern 14, momentarily shorting the two poles of the telephone line, and no surge voltage is applied to the input circuit pattern 12. Work like.

[0014]

[Effects of the Invention] As described above, according to the present invention, since the lightning arrester is constructed on a printed circuit board, space for parts can be saved and the device can be made at low cost. This has the effect of making it easy to set the voltage.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a lightning arrester according to an embodiment of the present invention.

FIG. 2 is a perspective view showing another embodiment of the invention.

FIG. 3 is a plan view showing a conventional lightning arrester.

[Explanation of symbols]

1 Printed circuit board 2 Lead wire 3 Common pattern for switching 4,5,6 Chip resistance 7 Individual pattern for low voltage 8 Individual pattern for medium voltage 9 Individual pattern for high voltage 10 Common pattern for discharge 11 Exposed part 12 Input circuit pattern 13 Double-sided printed circuit board 14 Telephone line connection pattern 15 Through hole

Claims (1)

[Claims] [Claim 1] A common discharge pattern made of copper foil and a plurality of individual discharge patterns facing the same at different distances are provided on a substrate, and the individual discharge patterns also have the same pattern as described above. A removable zero-ohm chip resistor is used to electrically connect and disconnect between the common pattern for switching formed of copper foil on the board, and the common pattern for discharge and the common pattern for switching are protected. A lightning arrester characterized by being connected to a circuit.