I put this into beginners because this is a semi stupid question.
Originally mention in this thread,
https://www.eevblog.com/forum/beginners/variable-regulator-pass-transistor/Was this circuit,
What i want to do is replicate it, I've attempted it but i fried the 2N2907, i figured out why, it was a mechanical fault, and so i intend to try again.
I want to use the LM317HV because i have a massive, the thing takes up a couple square feet, 7 amp transformer which when rectified to DC gives me 55 volts. This eliminates the LM338K (which i have) leaving me with only this as an option.
Toying with just the transistors in LTSPICE, that is to say omitting the LM317 because i cannot find a way to simulate it, the circuit works acceptably using the 1 ohm resistor in series with the LM317 and .15 ohm resistor to the transistor.
That gives me up to 4.5 amps out with safe margin, if i connect another 2n3055 in parallel to the first one but with the collector going through another .15 ohm resistor, this would give me 5 amps out while keeping the LM317HV well within it's bounds.
My questions are;
Will this work reasonably well for what it is?
Have i overlooked something? Particularly something that might lead to more magic smoke?
My aim here is not for perfection, though that would be nice, but instead to get 45V out. That leaving overhead for the resistive drop, the LM317HV drop and any other losses in the circuit. Can this circuit with my proposed modifications do that?
What about at lower voltages? Will the voltage drop inside the LM317HV, and it's wattage limits, be a problem? If so i have a variac i could use on the non-adjustable power supply feeding this circuit.
I have a handful of 2n3055 on hand,
hFE=110 Vf=534mV
hFE=110 Vf=534mV
hFE=50 Vf=608mV
hFE=63 Vf=495mV
hFE=25 Vf=500mV
hFE=54 Vf=515mV
hFE=297 Vf=525mV
hFE=449 Vf=505mV
I'm thinking the top two, because of how closely matched my transistor tester says they are. But they also have much lower gain than the bottom two
Thank you to anyone who has read this far, please and thank you for any help.
It might be an important note that this isn't about practicality as much as it is using what i got and learning from it.