circuit-designcomponentsidentification
For a project that I am working on, I need a circuit that can take a momentary pulse of voltage and then output a constant voltage until the other input is triggered. Kind of like a flip flop but with two inputs: 
So when a voltage is applied to A, P will output a voltage until B has a voltage applied to it.
Does such a circuit exist and if so, what is it called?
Thank You!
No, your circuit is still a edge-triggered circuit. The pairs NAND1+NAND2 and NAND3+NAND4 lock the state of D when the clock rises from to low to high. Changing D when the clock is high (after the rising edge) does not affect the output.
Let's start with Clk = 0, then is S=1 and R=1.
Now let D=0 during the rising edge of the clock:
S is still high, thus R=0 => Q=0.S is high, and R keeps low.The output of NAND4 will be kept high until the clock is low again because the input connected to R is low regardless of any change on D (after the rising edge).
Please note that the functionality of this circuit relies on the propagation delay of the gates.
There are all sorts of ways.
JK
simulate this circuit – Schematic created using CircuitLab
T (essentially a JK with both inputs tied together
D (Essentially a JK with the K inverted, and both tied together)
Note that the JK implementation ties the inputs of the first FF high, and this is not shown as an input on most counters.
Best Answer
As Turbo J said, the device performing that function is a SR latch. The CD4043 and CD4044 ICs may be what you're looking for. Then you'll have to add an inverter in order to generate the Q output. You can use the 74HC04 inverter.
simulate this circuit – Schematic created using CircuitLab
OTOH, if you need your P, Q voltages to be different from the A, B peak voltages then you'll have to implement some kind of logic level conversion. A simple transistor switch will do the trick. Even better, you can save the 74HC04 inverters by using complementary transistors for the switches.
There is also a synchronous version of the SR latch: the JK flip-flop. But it may not be what you're looking for.