• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

uln2003a can COM pin be GND?

Not open for further replies.


New Member
Most configurations have it so a voltage like +12V is connected to the COM pin of a darlington transistor array.

I don't quite understand the schematic of the darlington transistor array and i was wondering if it's possible to switch the grounds on-off rather then the power.

What i'm trying to accomplish is i have 4 loads i need to switch which have a power supply of 12V and 2 loads which are powered by 5V. Initially i designed my circuit using a number of 2n7000 mosfets and it worked great. Now i'm optimizing my design and it's cheaper to using a darlington array then using seperate mosfets for each device. Additionally, i've added some inductive loads (relays) so the internal clamping diodes are a plus.

Is it possible to have the darlington array switch grounds?

Thanks in advance!


Active Member
The 2003 outputs are NPN darlingtons with COMMON emitters, and open collectors. So the common must be negative or GND. The load connected between open collector and +power up to 50V.
Not open for further replies.

Latest threads

EE World Online Articles