Electronic – Where to buy an SR Latch


I am looking for a simple SR Latch. I'm new to electronics though and just doing a hobby project/teaching myself. Are SR Latches sold (I'm hoping to avoid building mine because I actually need at least 5) and if so where can I buy them (Radio Shack?) and what do I ask for? I link to a site with a part number would help too.

Per the comments. I have called Radio Shack and they said they didn't have them. The local big electronics store could only help me if I had a part number. I don't know if they actually can't help me or if I just don't know what to ask for. Is my best option just building them? I was kind of hoping I could just buy a small self contained item that was a SR Latch. If I were to wire them myself they would take up significantly more space.

Best Answer

RS latches have several parts in the industry-standard 7400 and CD4000 series, all of which are quad packages in old logic families:

Another alternative, with two parts in a package rather than 4, but more available in modern logic families (read: lower-voltages) would be to use a 74xx74 dual D flip-flop as an R-S latch by grounding its data and clock inputs, and using the PRE and CLR inputs as S and R inputs, respectively. In this case, I'd start with a 74HC74.