The current flow from collector to emitter in the NPN transistor when the positive supply is applied to the base is vital variations between the NPN vs PNP.

A PNP is used for the main pass transistor, but the circuit is easily converted to NPNs. The regulator can be shut down by shorting D1; the current will drop to whatever flows through R1.

The npn and pnp transistors used in the circuit should be high current- gain (hfe > 100) devices with minimum 2-A continuous current drive capacity (see the figure).

Zetex Semiconductors has introduced a series of miniature NPN and PNP transistors for MOSFET gate driving in latest generation power supplies. ZXTN and ZXTP transistors The first bipolars to be ...

A major current law has been rewritten thanks to the three-port transistor laser. Data the transistor laser generated did not fit neatly within established circuit laws governing electrical ...

The circuit monitoring the positive rail replaces npn with pnp devices. Best results are obtained using inexpensive dual transistors and 1% resistors for setting Iref and for Re1 and Re2.

All-optical transistor: Controling the flow of light with a novel optical transistor Date: November 12, 2010 Source: Ecole Polytechnique Fédérale de Lausanne Summary: Researchers have discovered ...