Improper installation of rectifier diode tightly attached to the printed board

The rectifier circuit shown in Figure 1 has a broken rectifier bridge and smoke from the filtering capacitor during use. Further inspection revealed that the rectifier bridge is heating up severely. Due to its pins being cut short and installed tightly against the printed board, the surrounding printed board has turned a burnt yellow color.diode

1. In circuit diagram 1, D1 and D3 conduct during the positive half cycle of AC; During the negative half cycle, D2 and D4 are conductive; The rectified current passes through two diodes simultaneously. Due to the forward voltage drop of ordinary rectifier diodes being about Iv, the voltage drop across the rectifier bridge is about 2V. If the output current of the rectifier bridge is 1.5A,  diodethe loss of the rectifier bridge is about 3W. It can be seen that the heat dissipation of the rectifier bridge itself should be considered. If the rectifier bridge is tightly attached to the printed board and too close to surrounding components (such as filtering capacitors), its heat cannot be effectively dissipated, which may cause overheating and damage. 2. Countermeasures: The pins of the heating element should not be cut too short, and the bottom should be suspended between the circuit board; diodeAt the same time, increase the distance between the rectifier bridge stack (S2VB20. html "target=" -blank "title=" S2VB20 ">S2VB20) and the surrounding components, as shown in Figure 20 and Figure 3. It can be seen that the shorter the lead, the smaller the current allowed to pass through. In addition, by using Schottky barrier diodes (SBDs) with low forward voltage drop for rectification, the voltage drop is only 0.5V, which can reduce losses and heat generation. Chengdu Qinghua Compilation  diode