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Provided you give it enough base current, it is rated at 4A continuous and 7A pulsed at 300uS/1.5% duty cycle.
The voltage is largely irrelevant as it's 32V rating is for the voltage dropped across it, rather than at it's output so it depends on what voltage you are regulating down from. The biggest concern would be not to exceed it's power rating (voltage dropped * current through it).
This little thing can do it, but it needs a very big heat sink. :roll:
Take care of the power dissipation of 36W at 25°C. When the case temparatur rise up, the power dissipation must going down or a heat sink is necessary, else the transistor will melt.
Thank you all!
I am thinking of using it in this PSU **broken link removed** (left hand side)
Do you believe the base is enough biased for 2.2A on 12v zener or about 4a at 24v zener?
That PSU will only deliver a few 100mA. Changing the Zener diode will alter the output voltage but to increase the current you would have to scale down the 1K resistor in the base of the power transistor and possibly also change the transistor below it to one with higher current rating. Your biggest problem will still be power dissipation. at 4A / 24V you would have to limit the input voltage to 33V and thats if you can keep the temperature below 25C.
Possibly a better solution and with fewer components would be to 'wrap' the transistor around either a 7812 or 7824 regulator so they share the load current between them. This would also have the benefit of thermal shutdown if they got too hot. If it has to be a variable voltage, wrap it around an LM317 instead.
When thinking about 24V at 4A (=96W) a switch mode PSU would be more efficient.
That PSU will only deliver a few 100mA. Changing the Zener diode will alter the output voltage but to increase the current you would have to scale down the 1K resistor in the base of the power transistor and possibly also change the transistor below it to one with higher current rating. Your biggest problem will still be power dissipation. at 4A / 24V you would have to limit the input voltage to 33V and thats if you can keep the temperature below 25C.
Possibly a better solution and with fewer components would be to 'wrap' the transistor around either a 7812 or 7824 regulator so they share the load current between them. This would also have the benefit of thermal shutdown if they got too hot. If it has to be a variable voltage, wrap it around an LM317 instead.
When thinking about 24V at 4A (=96W) a switch mode PSU would be more efficient.
Thanks Brian,
I am making a battery PSU with two 2.2A batteries connected in different configurations, in parallel, in series, or two independent batteries.
The regulator shown is a variation of the thrifty voltage regulator published in Elektor magazine and it can operate at an input voltage a few 10s of mV above the output voltage. This is very battery friendly and you end up with stable PSU (and more clean than the LM series probably) near to the battery voltage. In comparison the LM regulators require 2-3V greater input voltage than the output, which cannot be tolerated in this PSU.
The regulator is only needed to get adjustable lower voltages from the 12V or 24V configuration.
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