theory of operation of SRAM

in many ways, SRAM is simpler than DRAM, in the sense that each cell functions by itself without the need for refresh

however, in actual fact, ironically, it's harder to make a resistor than a transistor, in fabrication, so the resistor is made active (with constant current sources):

a really bad analogy often shown in textbooks

we can think of the above as cross coupled inverters:

what's wrong with the above?

a not so bad analogy: