T flip flop implemented using clocked SR from NAND gates

Thread Starter


Joined Mar 1, 2011
OK. I am attempting to make a toggle flip flop out of 74LS00 NAND gates, and the simplest way I can think of this is using a clocked SR flip flop with the R connected to Q' and the S connected to Q.

I saw the circuit for this in Forrest Mims' "Getting Started in Electronics". However, if I apply a clock signal to the remaining input of the clocked SR flip flop (the E input), no switching occurs. The outputs seem to both be stuck on Low. This happens both with my breadboard and Multisim 10.1.

Schematic of entire pertinent circuit is attached in PDF format.