PCB Assembling and Customer’s Defect Rate Reduction

Abstract

This thesis investigates the PCB assembling and use of dual varistors in the Printed Circuit Board Assembly (PCBA) of double door refrigerator to improve the surge protection and make the circuit reliable. Power line fluctuations and external factors such as lightning can cause voltage surges, which can lead to malfunction, inefficiency, or even damage to electronic components. To counter these risks, the research proposes a new design, in which two varistors are connected in parallel between the power input and supply lines. This is a good way to clamp the excess voltage to help protect the sensitive circuits from the transient overvoltage's. Several critical aspects of the methodology are highlighted: The selection of varistors with the right voltage ratings, energy absorption capacity, and response parameters; Design of an optimized PCB layout which accommodates the dual varistor configuration within a compact package; and thorough simulation and testing under transient voltage conditions. Prototype testing has confirmed that the dual varistor system can effectively suppress voltage spikes and safeguard electronic devices. Cooperation with manufacturers is an essential aspect of development process, and it is important that the design is developed correctly in the production process, and that it meets Circuit Design Rules (CDR). This partnership guarantees precise assembly and compliance with industry safety standards, enabling reliable and reproducible results. The results highlight the dual varistor configuration's ability to improve resilience and longevity of the electronics for the refrigerator. This helps prevent failures and maintenance issues, and maintains overall stability throughout the system's life. Also, the investigation focuses on the solution's compatibility with the highly demanding safety and performance standards of the consumer electronics industry. The new design not only enhances the durability and reliability of contemporary refrigerators but also creates a scalable model for surge protection of other consumer appliances. The dual varistor system is an important step forward in protecting sensitive electronic systems, enabling the creation of powerful and efficient appliances that cater to the needs of a safety-conscious consumer.