Browse Prior Art Database

POLARIZED CAPACITOR ORIENTATION SENSOR

IP.com Disclosure Number: IPCOM000007161D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2002-Feb-28
Document File: 3 page(s) / 116K

Publishing Venue

Motorola

Related People

E. D. Metcalf: AUTHOR [+2]

Abstract

This publication describes a sensor for detecting the physical orientation of polarized axial leaded capacitors in electronic assemblies.

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MOTOROLA Technical Developments Volume 21 February 1994

POLARIZED CAPACITOR ORIENTATION SeNSOR

by E. D. Metcalf and R. M. Geller

  This publication describes a sensor for detecting the physical orientation of polarized axial leaded capacitors in electronic assemblies.

  The present method of ensuring proper polar- ized capacitor orientation in a printed wiring assem- bly is to visually inspect the assembly. Visual inspec- tion is relatively slow and is unreliable because it is subject to human error, Improper capacitor instal- lation will cause premature failure of the capacitor at a higher level ofassembly or in customer use.

  The sensing method described here allows the orientation of a capacitor to be detected by using a magnetic sensor to detect the positive end of the capacitor. This method can be used to perform vir- tually instantaneous verification ofmany capacitors. The sensor can be used to verify capacitor orienta- tion before actual installation to ensure correct assembly.

  Typical construction of hermetically sealed capac- itors is shown in Figure 1. This capacitor configura- tion is a mature design. The use of the high perme- ability materials is necessary to make a reliable glass to metal seal. The high permeability materials, iron and nickel, at the positive end of the capacitor can

be used to modify a magnetic field.

  Figure 2 shows the Ibasic configuration of the capacitor orientation sensor. Permanent magnet Ml causes a flux density at the magnetic sensor Sl. When the positive end of a polarized capacitor is between the magnet Ml and the sensor Sl, the flux density at Sl will increase. The increased flux densit...