I used this releasable latch in a demonstration chamber. However, once the circuit is latched as described above, triggering the second input will turn OFF the corresponding Input at the AND gate invalidating its Output, which will now turn OFF, and providing that Trigger 1 has released, the circuit will unlatch. Should Trigger 2 be tripped, it will still have no effect. Once again, in the intial state, the AND gate will have one input that is already ON, so the circuit operation is unaffected. The operation is the same as above with the exception that an inverted input is fed to the second Input of the AND gate. It may be desirable to be able to make this Latch turn off for some applications, so I present now a modification to the above circuit. Now the OR gate has an Input that is ON and so the Output will remain in the stable ON state. This ON signal will now mean that the AND gate has both Inputs turned ON and so its Output will also turn ON. When the Trigger Input to the OR gate is triggered, the Output will Turn ON. This Output feeds into the second Input of the OR gate. Since the AND gate has only one Input that is ON, the Output will be OFF. The other input of the AND gate is unconnected and will be ON by default. The Output feeds back to one input of the AND gate. The operation of the circuit is as follows: In the initial state, the triggered Input of the OR gate is OFF and therefore, so is the Output. The 2 variations will become the basis of all the other complex elements that follow.Īlthough a latch is provided in BEE2, it has some undesirable traits, and for this reason I have choosen to provide my own built from an OR gate and an AND gate:. In the following discussion I will present a TIMER element that only fires ONCE regardless of how long the Input stays ON.įirstly, I will present a simple circuit and then a modification of this circuit. This is undesirable in most circumstances. When the countdown finalises, the Output turns ON momentarily.īecause of the nature of the TIMER element in BEE2, if the Input stays ON, the TIMER will count down repeatedly and trigger the Output. When the Input turns ON, the TIMER counts down the preset number of seconds. When the Input turns OFF the Output turns ON. The Output will only turn OFF if the Input is ON. The NOT gate has one Input and one Output. When BOTH Inputs turn OFF, the output will turn OFF. The Ouput will turn ON if either or both Inputs are ON. The OR gate has two Inputs and one Output. When either or both inputs turn OFF, the Output will turn OFF. The Ouput will only turn ON if both Inputs are ON.
The AND gate has two Inputs and one Output. Though most peple will have an idea what these logic elements are and what they do, I will describe each for the uninitiated.įor the logic gates, we will assume that initially all Inputs are OFF.
They are the AND gate, OR gate, NOT gate, and TIMER. There are 4 basic elements that I will be using to build the devices contained in this document.
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