JPS5939648Y2 - Through-hole continuity resistance measurement terminal - Google Patents

Description

[Detailed description of the invention] The present invention relates to a measurement terminal for through-hole conduction resistance, and in particular, improvements to measurement terminals attached to measuring instruments that measure the through-hole conduction resistance of electronic equipment components such as printed wiring boards that have through-holes. Regarding structure.

FIG. 1 is a perspective view of a conventionally used measurement terminal.

Reference numeral 1 is a current electrode, 2 is a voltage electrode, and 3 is an insulating spacer, which are sandwiched and are in contact with each other.

Reference numeral 4 represents an insulating tape that covers the aforementioned champion, and reference numeral 5 represents a measuring cord.

This conventional measurement method using measurement terminals involves inserting two measurement terminals into both ends of a through hole, passing a constant current between the current electrodes by contact with the inner wall of the through hole, and measuring the potential difference between the voltage electrodes to determine the continuity resistance. It was a search for.

For this reason, in conventional measurement terminals, the position of the current electrode is biased to one side of the through-hole, so that the current does not flow uniformly through the through-hole and tends to have a value larger than the true conduction resistance value.

Further, it has the disadvantage that the measured value changes depending on the installation position of the measurement terminal.

An object of the present invention is to provide a measurement terminal with stable measured values.

According to the present invention, a plurality of conductive plates for current measurement and conductive plates for voltage measurement each having an end face along the conical face are insulated from each other in a columnar insulator having a conical end shape, and each end face is insulated from each other. are arranged radially around the apex of the conical surface and exposed on the conical surface, and a plurality of the currents are applied to target positions on both sides of a pair of conductive plates for voltage measurement, which are arranged facing each other on substantially the same plane. A through-hole conduction resistance measurement terminal is obtained, which is characterized in that a conductive plate for measurement is arranged.

Hereinafter, one embodiment of the measurement terminal according to the present invention will be described with reference to FIGS. 2 and 3.

That is, both current and voltage electrode plates are trapezoidal and have the same dimensions, and are made of a highly conductive material such as copper.

For example, six current electrode plates 6 and two voltage electrode plates 7 are arranged.

One end of the electrode plate formed as the l1ffl terminal is formed into a conical shape.

This conical tip becomes the tip of the measurement terminal.

On the other hand, on the opposite side of the electrode plate, in the case of current electrode plate 6, 6
One end of the lead wire of a 6Ω fixed resistor 8 is connected in series to each of the plates.

Further, in the case of the voltage electrode plates 1 disposed facing each other on the same plane, the two electrode plates are each connected to one end of the shorting line 9.

The other ends of the shorting wires 9 are connected in common and connected to the measurement cord 5.

In order to insulate and fix the electrodes 6 and 7 from each other, the space between each electrode plate is then filled with an insulating material such as epoxy resin 10.

That is, this insulator 10 is fixed in an electrically insulated state with each electrode plate symmetrically and with the tip of each electrode plate exposed as a contact portion with a through hole.

Therefore, current electrode plates are arranged at symmetrical positions on both sides of a voltage electrode plate within a columnar insulator having a conical tip, and the end face of each electrode plate is exposed radially on the surface of the conical insulator.

Next, the principle of measuring conduction resistance using the measurement terminal of the present invention will be explained.

Generally, when measuring a sample of a low resistance part such as a through hole of a printed wiring board, the voltage drop method is used.

In this method, a constant current is passed through the sample and the resistance value is determined by measuring the potential difference between two points on the sample.

When the measuring terminals of the present invention are brought into contact with both ends of the through hole, a constant current is supplied from the measuring device body to the through hole.

This constant current is shunted and flows into the current electrode plate 6 disposed at one symmetrical position that contacts the end of the through hole, and flows out from the current electrode plate 6 disposed at the other symmetrical position.

The magnitude of the shunt current flowing through each current electrode plate 6 is
It is determined by the contact resistance between the current electrode plate 6 and the through hole and the resistance 6ρ of the fixed resistor 8.

However, since the contact resistance of the contact portion is extremely small compared to 6Q, it hardly affects the current shunting.

Therefore, the current shunting is dominated by the 6!2 fixed resistors 8.

Therefore, the shunt currents are of equal magnitude.

As described above, according to the present invention, even current is supplied to the through holes from symmetrical positions, so that the current distribution flowing through the through holes becomes uniform.

Since the potential difference is measured within this uniform current distribution,
The effective length of the current path is equal to the dimensional length of the through hole, and the true conduction resistance value can be determined.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional measurement terminal, FIG. 2 is a perspective view of the measurement terminal of the present invention, and FIG. 3 is a perspective view showing the internal structure of the measurement terminal of the present invention. DESCRIPTION OF SYMBOLS 1...Current electrode, 2...-Voltage electrode, 3...Insulating spacer, 4...Exterior insulation tape, 5...Measurement cord, 6...Current electrode plate, 7... Voltage electrode plate, 8.
...Fixed resistor, 9...Short-circuit wire, 10...Epoxy resin.

Claims (1)

[Scope of utility model registration request] A plurality of conductive plates for current measurement and conductive plates for voltage measurement each having an end face along the conical face are insulated from each other in a columnar insulator having a conical end shape, and each end face is connected to the conical face. A plurality of current measuring conductors are arranged radially around the apex to be exposed on the conical surface, and at target positions on both sides of the pair of voltage measuring waveguide plates, which are arranged facing each other on substantially the same plane. A through-hole conduction resistance measurement terminal characterized in that a plate is arranged.