I had a huge eureka moment when I realized that RMS voltage = Peak voltage * sin(45°) I haven't really heard an electronics teacher point that out but I think it's a really intuitive way to think about it.
A couple of observations: 1. When designing do not make generic assumptions about component characteristics such as rectifier diode forward voltage drop - read the data sheets. For example, the Vishay data sheet for 1N4000 series diodes lists Vr = 1.1 volts at 1.0 amp so Vr = 0.7 amps is not a valid design assumption. 2. Your voltage analysis seems to have completely neglected the ripple voltage on the filter capacitor. Even if the transformer and the diodes each had 0 ohms resistance, as the load current increases the effective voltage across the filter capacitor will drop. To determine the required transformer secondary voltage you need to consider several things: the operating range of your incoming mains voltage (often between +/- 6% to 10% depending on location), the transformer regulation characteristics, rectifier forward voltage drop, filter capacitor ripple voltage and then the requirements of the chosen regulator topology.
Thanks for this deep dive into power supply design. Your explanations are the clearest I've yet seen. Now I understand why, in a different video series on linear power supply design, multiple pass transistors were employed in parallel --since each one of the transistors in such a configuration dissipates a portion of the total heat.
Switching supplies are very useful until you start playing with sensitive pre-amplifiers. The switching supplies are very 'noisy' and this 'noise' gets amplified along the input signal. Linear supplies are much cleaner. Suggestion - have BOTH if you can afford it. 😀
