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I've recently been doing some online tasks but I am really struggling to understand how build this circuit in multisim. I am also struggling to calculate the values listed in 2. and have tried to find out for myself but have had no luck. I also don't know where these values are calculated, "for each components"?? I had a go but really don't know if I'm even following the correct steps given.


closed as off-topic by Leon Heller, Dave Tweed Sep 2 at 11:16

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    \$\begingroup\$ This looks so much like your homework - You learn by doing it ie an important part is the process. See electronics.stackexchange.com/q/455740/152903 \$\endgroup\$ – Solar Mike Sep 2 at 9:14
  • \$\begingroup\$ Are you not doing some course to learn how to do this? It's not about luck. \$\endgroup\$ – Finbarr Sep 2 at 9:16
  • \$\begingroup\$ I am doing a free online course if you must know, im wanting to do this for myself and have tried for hours but i know im not on the right track. I need some guidance in order for me to actually learn anything. \$\endgroup\$ – JakeeYm Sep 2 at 9:16
  • \$\begingroup\$ You would likely get more help on here if you post your attempts with any calculations/reasoning/guesses you’ve made. As Finbarr has said, you really need some lectures on this task. \$\endgroup\$ – David777 Sep 2 at 9:35
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    \$\begingroup\$ Homework questions with no attempt at a solution posted are closed. \$\endgroup\$ – Leon Heller Sep 2 at 9:38

You have a common bridge rectifier and bulk storage capacitor, this is your unregulated supply, by controlling the transformer turns you can control what this voltage is,

You would ideally size the voltage, or the capacitor size to ensure with your known load it never falls below your regulation "Dropout Voltage", e.g. a linear regulator trying to output 9V might misbehave when its input falls under 10.5V

The exact way you make the regulators are up to you, its likely to involve active devices e.g. transistors and diodes / zener diodes to give you a starting point for what to look for

As to the nominal value, power and voltage rating, each component has a power and a voltage rating where if exceeded will damage the device, e.g. a 1/4W resistor can only handle a quater watt of heat, go much above this and it may de-solder itself off a PCB,

Voltage rating would more apply to capacitors, the lower the voltage rating, the cheaper and smaller, the rule of thumb is give yourself a headroom of atleast 20% on the voltage rating, so find the maximum voltage you expect, and round it up to the nearest normal value atleast 20% higher, this is headroom for things like spikes and surges on the mains power

Nominal value would be either average voltage / power or possibly the specific component values. depending on context.

  1. Refer this link for one method using bridge rectifier and zener diode as regulator.


  1. Refer this link for another method using bridge rectifier and 7809 as regulator.


You can keep rectifier and filtering circuit same but change the last regulation methods either zener or 7809

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    \$\begingroup\$ Usually when someone posts a homework question, answers are not just given as the OP will not learn anything. Try and make answers to homework questions a series of hints to help OP arrive at the correct conclusion. This also doesn't address the calculations of components (voltage/power rating, values etc) \$\endgroup\$ – MCG Sep 2 at 10:41
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    \$\begingroup\$ Also, answers that are mainly links to other websites are discouraged. The links you provide could go bad tomorrow. Instead, provide the important content yourself. \$\endgroup\$ – Elliot Alderson Sep 2 at 12:02

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