The right way to control an LED is with a discrete transistor or using an integrated circuit that is specifically designed for driving high-current loads. This whole approach is OK for a hobbyist situation but it's not suitable for high-volume manufacturing if you care about reliability. Be sure that you don't exceed the total current limit of the entire packaged device. In the absence of data sheet specifications you will need to try some experiments. This tutorial will show you how quickly you can create and test a circuit using LogicWorks.
#Logicworks 5 led series
To be safe, you will need a series resistor to limit current. Some manufacturers will provide graphs of typical output current as a function of output voltage. The manufacturer doesn't provide min/max values for this situation because that's not really how the gates are supposed to be used. Now, if you no longer care about maintaining valid logic levels where the gate output is connected to the LED then you can source considerably more than 4mA from the gate output. Your second solution is the more correct one. So, if you want to drive an LED from a gate output you can not also use that gate output as a logic signal. You need to remember that the HC gates cannot supply more than 4mA and provide valid logic levels at the same time. (The 74HCxx series seems to support that.) All of which does nothing to solve the current problem.ĭo I need one of the level-translating logic gates? Or do I need to build something even more elaborate than that? The components we will be using include Binary Switches, AND gates, OR gates, LED’s, and wires.
#Logicworks 5 led software
(My knowledge of analogue electronics is far too weak to know if that would work.) Alternatively I could just run all the logic at 2 V instead. Before actually building the circuit, we will map it in the Logicworks 5 software to make sure it works and later get it checked off by the TA.
![logicworks 5 led logicworks 5 led](https://i.pinimg.com/originals/bc/fd/68/bcfd685340171ed57221f5904d586927.jpg)
Perhaps I could use a resistor to work around the voltage difference. Also, it appears 74HCxx can only supply up to 4 mA, whereas most LEDs seems to draw drastically more current than that. Trouble is, I'm planning to use 74HCxx logic running at 5 V, whereas it looks like most LEDs want to run at ~2 V. Now only the output of the buffer has to deal with the load from the LED the AND gate is blissfully unaware that anything has happened. The second problem looks like it ought to be trivial (if inconvenient) to solve:
![logicworks 5 led logicworks 5 led](https://s3.manualzz.com/store/data/025684817_1-92a0012e2822a46b1771cee981d1eb09-360x466.png)
Will the load from the LED distort the output so much that I can't connect it to any other gates?.Can the logic gate's output actually deliver enough power to drive the LED? (Sure, LEDs are very low-power.Simulate this circuit – Schematic created using CircuitLab What is the correct way to connect an LED to a logic circuit?