Question

You have ac voltage of 230v from main supply and you want to power your two electronic system same time. Your electronic system 1 (computer) need 12v to operate and your electronic system 2 (study lamp) need at 5v to operate. Design the ac-dc converter using the stepdown transformer with an input voltage of 230v and frequency of 50hz, and two output voltage of 12v-1a and 5v-1a.

Answer 1

To design the AC-DC converter using a step-down transformer for the given specifications, we can follow the following steps:

Determine the turns ratio of the transformer:

Since we need to step down the voltage from 230V AC to 12V DC and 5V DC, we can use the turns ratio formula:

Np/Ns = Vp/Vs, where Np is the number of primary turns, Ns is the number of secondary turns, Vp is the primary voltage, and Vs is the secondary voltage.

For 12V DC output: Np/Ns = 230/12

Np/Ns = 19.17

For 5V DC output: Np/Ns = 230/5

Np/Ns = 46

We can choose a transformer with the nearest turns ratio, such as 20:1 for 12V DC output and 45:1 for 5V DC output.

Select the diodes and capacitors:

We need to choose diodes and capacitors that can handle the current and voltage of the output. For example, we can use 1A diodes and 1000uF capacitors for both outputs.

Build the rectifier circuit:

We can use a full-wave rectifier circuit with the diodes and capacitors to convert the AC voltage to DC voltage.

Connect the load:

Finally, we can connect the load, i.e., computer and study lamp to the output terminals of the rectifier circuit.

Therefore, the complete AC-DC converter using a step-down transformer with an input voltage of 230V and frequency of 50Hz, and two output voltage of 12V-1A and 5V-1A can be designed using the above steps.