| 摘要 |
917,471. Circuit assemblies; potted resistors. NATIONAL CASH REGISTER CO. March 10, 1961 [March 30, 1960], No. 8790/61. Class 37. A three input AND gate comprising two resistors and a diode is first enveloped in a wax, plastic elastomer or polyvinyl alcohol material 14 and then embedded in a plastic resin 15 which may be one of the epoxies, acrylics, or polyesters; the solubility properties of the plastic resin being different from those of the enveloping material 14. In order to repair or replace one of the components of the gate the plastic resin 15 around the relevant component is dissolved by a solvent, to which the enveloping material 14 is impervious, and the exposed enveloping material is then removed either by dissolution or by mechanical breaking. |
