SU1250992A1 - Device for contactless determining of location of break of current conductive track of lacquered printed-circuit board - Google Patents

Abstract

This invention relates to a measurement technique. The purpose of the invention is to improve the accuracy of determining the place of break of the conductive path of the printed circuit board and simplify the functional scheme of the device. The device contains a generator 1, a measuring unit 2, including a resistor 3, a DC amplifier 4, capacitive sensors 5 and 7 and an analyzer 6. The refining of the measuring unit 2 in the form of a DC amplifier and the formation of new connections in the device greatly simplifies the process of manufacturing printed boards 2 Il. § CO With

Description

The invention relates to a measuring technique and can be used for contactless determination of the location of a break in a conducting track of a varnished printed circuit board during the operation of radio equipment assemblies mounted on a printed circuit board.

The purpose of the invention is to improve the accuracy of determining the location of the break of the conductive path of a varnished printed circuit board without disturbing the integrity of the coating and simplifying the functional diagram of the device.

FIG. 1 shows a block diagram of the device; in fig. 2 - timing diagrams for the operation of the device.

A device for contactless determination of the location of a break in a conductive path of a varnished printed circuit board contains a generator of square alternating sign-pulses, a measuring unit 2 including a reference resistor 3 (Rp) and an amplifier A of direct current, a capacitive sensor 5, an analyzer 6, capacitive sensor 7.

The device works in the following way.

When the power is turned on, the generator 1 begins to produce two successive rectangular alternating alternating pulses of the same length, different amplitude and shift

180 pulses relative to each other, the sequence of hectares of 1 pulses from the first output of the generator has an amplitude and, 1 V, the pulses from the second output have an amplitude of U 13 V,

Capacitive sensors 5 and 7 are mounted on the track to be tested and advanced along it. The resistance of the conductor path Cd together with the capacitances Cd of the sensors 5 and 7 form a negative feedback of the operational amplifier 4, at the input of which the reference resistor 3 (Cd) is turned on,

The output voltage of the measuring unit 2 in the case of integrity of the tested conductor

0

and

ng.

(t)

 -,

to"

OSD

(.norm)

if cd is several ohms and cd is a few picofarads, the value of uyji is not much different from the value of 1B,

In the event of a break of the inspected conductor, the resistance of the Cdd track tends to infinity, then the gain of the operating and

The first amplifier k is determined by the direct gain of the operational amplifier. In this case, the output voltage of the measuring unit 2 5 will be determined by the voltage of the operational amplifier E, g, p:

IB2 Soarmv) For K5AD series microcircuits) ac is equal to ± 15 V,

In equal stress ratio

 and ,, (i.e. in the place - (obpfcie)

dug track) output voltage

The comparator jumps its state from zero to the voltage of the analyzer U, stepwise.

yen. Kfi

Claims (1)

Formula invented A device for contactless determination of the location of a break in a conductive track of a lacquered circuit board, comprising a generator, two capacitive sensors, a measuring unit, an analyzer, characterized in that, in order to improve the accuracy of determining the break point of the conductive path of a varnished printed circuit board, the form of a DC amplifier, the first input of which is connected through a reference resistor to the first output of the generator, the second of which is connected to the first input of the analog the second input of which is connected to the output of the DC amplifier, the second input of which is grounded, the output of the first capacitive sensor is connected to the first input of the DC amplifier, the output of the second capacitive sensor is connected to the output of the DC amplifier, the first and second capacitive sensors are set to control object , "Z Editor L. Pchelinska Make up: .- .KHaenko Techr € d L. Dgokova  :;., kaz 4405/41 Circulation 728 Subscription VNIIPI USSR State Committee for inventions: - :. og-krggy 113035, Moscow, Zh-35, Raushsk nab, 4/5 Production and printing company, Uzhgorod, Proektna str., 4 Proofreader I. Muska