Transistors - Electronic Circuits Projects Diagrams Free

mstechca · 23rd April 2003, 04:48 PM

When I buy BJT transistors from the store, the price label contains the following: amps, voltage, and polarity (NPN or PNP).

The transistors I buy are marked 100ma and 500ma.

Does this mean that the marked amp value is the minimum value required to turn it on?

**kinjalgp** · 23rd April 2003, 05:35 PM

No, that is the maximum current that it can handle. In other words, it is the maximum value of collector current for which the transistor operates safely. Beyond that it will go into "thermal run-away".

Phasor · 25th April 2003, 12:57 AM

Also - the voltage is the maximum collector-emitter voltage. If you exceed that, it can fry :P

windozeuser · 25th November 2003, 01:13 AM

AHHHHHHHHHHHHHHHHHHHHHHHHHHH! THE OLD TRANSISTOR BARN FIRE :shock:

Optikon · 25th November 2003, 05:55 PM

Quote:

Originally Posted by kinjalgp

No, that is the maximum current that it can handle. In other words, it is the maximum value of collector current for which the transistor operates safely. Beyond that it will go into "thermal run-away".

Just to be clear, this is not necessarily so. Thermal runaway is a power dissipation related problem. I can find an operating point such that the collector current is less than the maximum rated and still cause thermal runaway.

**kinjalgp** · 25th November 2003, 06:32 PM

Yes that is also possible.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

23rd April 2003, 04:48 PM	(permalink)
mstechca	Transistors When I buy BJT transistors from the store, the price label contains the following: amps, voltage, and polarity (NPN or PNP). The transistors I buy are marked 100ma and 500ma. Does this mean that the marked amp value is the minimum value required to turn it on?

23rd April 2003, 05:35 PM	(permalink)
kinjalgp	No, that is the maximum current that it can handle. In other words, it is the maximum value of collector current for which the transistor operates safely. Beyond that it will go into "thermal run-away". __________________ "There is no way to peace, peace is the way!"

25th April 2003, 12:57 AM	(permalink)
Phasor	Also - the voltage is the maximum collector-emitter voltage. If you exceed that, it can fry :P

25th November 2003, 01:13 AM	(permalink)
windozeuser	AHHHHHHHHHHHHHHHHHHHHHHHHHHH! THE OLD TRANSISTOR BARN FIRE :shock:

25th November 2003, 06:32 PM	(permalink)
kinjalgp	Yes that is also possible. __________________ "There is no way to peace, peace is the way!"