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You will need

• - a guide to semiconductor diodes;
• - calculator;
• - paper;
• - a pen.

Instructions

1

Define the basic parameters of the futurerectifier: the output voltage (determined by the voltage of the transformer and the rectifier design) and the developed power, over which calculate the required maximum current of the diodes. To do this, divide the required power by the amount of the active voltage at the maximum load. Get the estimated value of the maximum current flowing through the rectifier.

2

Determine by what scheme you will makerectifier - half-wave (quarter-bridge), full-half (half-bridge with mid-point), full-wave full-bridge. Each scheme has its advantages and disadvantages.

3

In the half-wave (quarter-bridge) rectifierinstall one diode, such a rectifier requires less space. When calculating the maximum diode current, keep in mind that the entire load current flows through it. The rated current value (according to the reference book) should exceed the design value of the maximum current by 30%.

4

In a full-wave rectifier with an average pointinstall 2 diodes. In such a rectifier, the current flows alternately through both diodes. But such a rectifier circuit requires the presence of a special transformer with a tap from the middle of the secondary winding.

5

In the full-wave rectifier (full bridge)install 4 diodes. This circuit produces a current with twice the ripple frequency, which is then easier to reduce with a smoothing capacitor or stabilizer.

6

In all cases, the nominal voltage of the diodesshould be 2 times the maximum voltage at the output of the rectifier. Such a voltage reserve is done due to the fact that when heating the breakdown voltage of the diodes decreases.

7

Determine by reference the maximum currentyou used a diode, in which it can work without a radiator. If more current flows through your diode in your rectifier, install it on the radiator. The size of the radiator is determined depending on its design and the material from which it will be made.

Tip 2: How to calculate the current in the transformer

If you decide to make a transformer yourself, then you need to know some things about this device, including how to calculate current at transformer, as will be discussed below.

Instructions

1

Find out if you were previously unaware of this, the maximum current load and voltage on the secondary winding. Multiply current maximum load (in amperes) by a factor of 1.5 - find out the winding of the second transformer (in amperes).

2

Calculate the power consumed by the rectifier from the secondary winding of the transformer. To do this, multiply the voltage of the secondary winding by the maximum currentCalculate the power of the transformer. To find out the power, multiply the maximum power on the secondary by 1.25.

3

Calculate the value of the tone on the primary winding. To do this, the power obtained in the previous paragraph should be divided by the mains voltage on the primary winding. Calculate the parameters of the core area of ​​the magnetic wire. It is necessary to take the power of the transformer in watts and multiply it by 1.3.

4

Calculate the transformer by the numberTurns on the primary winding, which you will have. In order to determine the number of turns on the primary winding, the primary winding voltage should be divided into the cross section of the core, and then the result multiplied by 50.

5

Calculate the transformer by the number of turnsSecondary winding. Take the voltage of the secondary winding and divide this number by the section of the magnetic wire, then multiply the result by 55. Set which wire cross section is needed for the winding. To do this, take the value currenta, which passes through the winding, and multiply this number by 0,02. Ready, now you, have, an approximate idea of ​​how to calculate current at transformer.