BETAPIN 1 · Ground
EmitterE
Function
Emitter terminal of the bipolar transistor.
How to connect
Connect to common ground in the low-side example.
Electrical note
TO-92 pin 1 becomes SOT-23 pin 2.
High-voltage NPN transistor
MPSA42 Pinout
Explore MPSA42 pins, signal names, electrical functions and connection guidance for each package.
Package view
3Physical pins
MPSA42BKTO-92
Manufacturer-referencedDiotec Semiconductor
Pin diagram
Select a pin to explore its connection
Highlight
MPSA42BKTO-92Front view · flat face · E1, B2, C3
MMBTA42SOT-23Top view · rotated 90° · B1 upper left, E2 lower left, C3 right
Click a lead or use the arrow keys. Front view · flat face · E1, B2, C3
PIN 2 · Base / control
BaseB
Function
Base current controls the collector current within the circuit operating region.
How to connect
Drive through 4.7 kΩ; connect 100 kΩ from base to emitter.
Electrical note
TO-92 pin 2 becomes SOT-23 pin 1.
PIN 3 · Collector / load
CollectorC
Function
Load-current terminal of the transistor.
How to connect
Sinks current from the LED and its resistor.
Electrical note
Collector remains physical pin 3 in both selected packages.