TL 072 pin 1 not marked

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
B

barber02

Member
Joined 2018
I recently bought some TL072 ic from mouser and to my surprise there is not a pin 1 identifier. I haven’t been doing this work for very long but this is the first time I’ve seen this. Am I missing something obvious that I should just already instinctively know? I have already installed the new chips on the board (taking a guess) and I’m curious if I have the new chips installed correctly

David
 

Attachments

  • image.jpg
    image.jpg
    1 MB · Views: 138
M

MarcelvdG

Member
Joined 2003
It's a pity that you already soldered them into a circuit, because the other stuff on the board may obscure things, but you could use a multimeter's diode test to check the polarity of the substrate diode between the upper left and lower right pins. It should have its cathode connected to pin 8 and its anode to pin 4 so it is in reverse when you apply a supply voltage.
 
M

MarcelvdG

Member
Joined 2003
Thinking more about it, it doesn't really matter that they are already in a circuit. If you should measure a diode between positive and negative supply that is connected in forward, you know that there is something terribly wrong, so when the rest of the PCB is OK, it must be the TL072s.
 
B

barber02

Member
Joined 2018
So I finally was able to get back out to the shop and check for the bevel edge and I found it. It looks like I got lucky and got the chips on the board in the correct orientation. The bevel edge is on the left. Talk about dumb luck.

Thanks for the help everyone. Much appreciated.

David
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom