Power Primary Vpp Primary I Primary Vpp Secondary CT Trans

Power Primary _____________________

Vpp Primary

I Primary ______________

Vpp Secondary CT Transformer ___________

Power Secondary CT Transformer _______________

I Secondary CT Transformer ____________

Power Dissipated Transformer ______________

Power Dissipated Full Wave Bridge Rectifier ___________

Vpk Output Bridge Rectifier ______________________

Power Dissipated + 15 VDC 15? 20 Watt Resistive Load ______________

Power Dissipated +8 VDC 10? 2 Watt Resistive Load ______________

Power Dissipated – 12 VDC 10? 2 Watt Resistive Load _____________

Power Dissipated – 5 VDC 4? 2 Watt Resistive Load ______________

Fuse size (Primary) with 25% Service Factor, __________

Power Dissipated LM7808 Linear Rectifier _________________

Power Dissipated LM7815 Linear Rectifier _________________

Power Dissipated LM7905 Linear Rectifier _________________

Power Dissipated LM7912 Linear Rectifier __________________

please show work to fully understand

Solution

Four Output Isolated Power Supply

First, some notes about electrical safety.

This project uses wall AC power, the DANGEROUS stuff. Please follow the recommendations below when building this project.
Use a 3 prong AC cord and make sure the green wire safety ground is connected solidly to the enclosure.
Keep in mind there is 120 VAC on some of the traces! Mount the PC board on round or hex standoffs at least a ¼ inch high by at least ¼ inch diameter with 6-32 threads. DO NOT use adhesive back plastic standoffs, they are not reliable or strong enough for a board with two transformers on it!
You must use a strain relief for the AC cord. This prevents the cord from getting cut on the sharp edges of the metal enclosure and also prevents the cord from getting ripped off the PC board.

Electrically, this is a very simple circuit times four. Transformer, to bridge rectifier/cap, to regulator with filter cap on regulated output, to the jacks.
The transformer should be selected to provide some margin for voltage drop across the regulator. The PCB layout assumes use of readily available Split Pack PCB mount transformers, which are available in a wide range of voltages. The following table summarizes my recommendations. Note that each transformer provides 2 voltage sources, since the 2 secondary windings are isolated and can be used independently. The Mouser catalog page does not state this (it shows series and parallel connections), but it works fine.