During calculation of the scheme of the power supply it is important to calculate correctly parameters of the diodes installed in it. It is necessary to take into consideration the maximum tension of the diode, the maximum current of the diode and also power of dispersion of diodes on which their radiators pay off.
It is required to you
- - reference book on semiconductor diodes;
- - calculator;
- - sheet of paper;
- - handle.
Instruction
1. Determine key parameters of future rectifier: output voltage (is defined by tension of the transformer and a design of the rectifier) and the developed power on which calculate necessary maximum current of diodes. For this purpose divide the size of necessary power into the size of the operating tension at the maximum load. Receive the rated size of the maximum current going via the rectifier.
2. Define according to what scheme you will manufacture the rectifier – one-half-period (chetvertmost), two-half-period (the halfbridge with an average point), the two-half-period full bridge. Each scheme has the advantages and shortcomings.
3. In a one-half-period (chetvertmost) the rectifier install one diode, such rectifier demands less place. When calculating the maximum current of the diode keep in mind that all load current goes through it. The passport size of current (in the reference book) has to exceed the rated size of the maximum current for 30%.
4. With an average point install 2 diodes in the two-half-period rectifier. In such rectifier the current goes alternately via both diodes. But such scheme of the rectifier demands existence of the special transformer with branch from the middle of a secondary winding.
5. Install 4 diodes in the two-half-period rectifier (full bridge). This scheme gives current with the doubled frequency of pulsations which then is easier for reducing by means of the smoothing condenser or the stabilizer.
6. In all cases the passport tension of diodes has to exceed twice the maximum tension at the output of the rectifier. Do such stock on tension because when heating tension of breakdown of diodes decreases.
7. Determine by the reference book the maximum current of the diode used by you at which it can work without radiator. If in your rectifier via the diode there is bigger current, establish it on a radiator. Determine the size of a radiator depending on its design and material of which it will be made.