What limit how much current I can pull? Heat of the LM or the fact it has 1/4 watt resistor/parts?
I don't have the exact specs but you can use less voltage to get the same output if you feed it AC vs DC. Why is that?
Why would the circuit care about ac or dc, since its has just your usual 4 diode (standard black with silver band size of 1/4 resistor types) regulator before the LM?
If I keep the circuit under liquid nitrogen with a huge cap will I be able to pull huge spikes of current and then sustain huge loads?
While we are on it, I still don't understand dave's video where he makes a both voltage AND current regulating circuit with two LM317s. How does the part know what it supposed to regulate if its just 3 pins?
So many questions.......
Q1
A1 simple answer is the weaks part in the current path. If the part is in the path that outputs current, it must be able to continuosly sustain that current. Some parts may overheat.
If you push parts beyond their specifications.
Some parts like LM317 will simply shutdown when they get too hot.
Q2
A2 There is a missconceptiin here. The bridge rectifier in the psu will drop the same voltage whether it is AC or DC.
The problem may be with the AC voltage measurment. DMM will display the rms or avaerage but if you look with a scope the peak is higher than the dmm value.
Q3
A3 The diodes are a rectifier circuit. It converts negative voltage into positive (for a 4 diode rectifier). So you can feed the circuit with AC or DC. AC will also vary the voltage so it will need a capacitor to hold the voltage up inbetween the voltage drops of the AC waveform. The cap is not needed if fed with DC.
Q4
A4 No. The psu circuit will still be limited by the weakest part in the current path of the psu. The liquid nitrogen will just allow higher continuous power/current because you have better cooling. It will not allow high pulsses of currents, that will always be limited by the components.
Q5
A5 ledtester explained how the 3 pin LM317 regulates voltage or current.
It is not easy to make a psu with both V regulation and current limit using the LM317.
I would not advised it.