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Screech said:Is it normal for a T0-220 type transitor to get very hot when running it at 12 volts @ 0.5 amps with heatsink?
The transistor is rated at around 3 Amps.
Even a T03 gets hot 12V @ 0.5 Amps ( no heatsink).
It's rated at over 10 Amps. :?
Why as heat?Assuming you have 12V across the transistor, and 0.5A through it, the transistor will be dissipating 6W as heat - bear in mind that's about 1/3 of many soldering irons!.
Screech said:Why as heat?Assuming you have 12V across the transistor, and 0.5A through it, the transistor will be dissipating 6W as heat - bear in mind that's about 1/3 of many soldering irons!.
Later, I added a 9 volt regulator a between the transistor and 0.5 @ load.
(12volts straight thru PNP transistor , to 7809 voltage reg, to 0.5 amp load)
The transistor still got hot, but the voltage regulator did not.
how do you know what size heatsink is required for the amout of wattage.
my catalog shows them in Thermal resistance.
eg t03 type as 7.3 degreesC/W
What does that mean?
I notice that bigger heatsinks are rated with smaller values.
Please post your complete circuit so we can see what you're doing
Maybe.Is it normal for a T0-220 type transitor to get very hot when running it at 12 volts @ 0.5 amps with heatsink?
The transistor is rated at around 3 Amps.
Even a T03 gets hot 12V @ 0.5 Amps ( no heatsink).
It's rated at over 10 Amps.
Is this normal?
Thanks
Screech said:Please post your complete circuit so we can see what you're doing
you are looking at it, (above)
the top resitor is is used to set the 0.5 Amps from emitter to collector.
the bottom resisor is the load (resistence wire) 2 ohms.
This is a REALLY bad looking 'design', I'm not surprised it doesn't work
Presumably what you want is a constant current source?, to provide a 0.5A constant current to a heating element?.
But what EXACTLY are you trying to do?.
Screech said:This is a REALLY bad looking 'design', I'm not surprised it doesn't work
Presumably what you want is a constant current source?, to provide a 0.5A constant current to a heating element?.
But what EXACTLY are you trying to do?.
The transistor will be an electronic supply switch for a different circuit.
I'm trying to simulate a 0.5 amp load to see how hot my transitors will get at that load.
It's just simpler to use resistance wire instead of 25 leds, 10 ic's, 2 voltage regulators & , etc..
My original idea was to use a t0-220 type but it gets too hot even tho its rated at 40 watts with that little heatsink.
What's the deal with D7? C1 won't do its job with a diode in series with it.danielsmusic said:here is the regulator i built