Guess I can't simulate my half adder either 

To successfully run simulations in EasyEDA, you need to read and play with the examples in the Simulation Tutorial,  (3) in (2) in: [https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a](https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a)

Your transistor version is only a NOT gate in the sense that it will not operate at all even if the simulation were configured correctly. It would not only not work but would probably destroy the transistor in a real circuit. I recommend that you also study some electronics resources that cover basic bipolar transistor theory and applications. Here is a short list: [https://easyeda.com/forum/topic/Useful-learning-resources-78a07f9ed4104ce9b15fc7584ac67003](https://easyeda.com/forum/topic/Useful-learning-resources-78a07f9ed4104ce9b15fc7584ac67003)

@andyfierman   Could you elaborate? I have an input, an output and power running from source to the ground. Just like in all schemes of a NOT gate

It might help you to compare these two schematics. Yours:  From some other source: 

@andyfierman what's the difference? I have input Logicstate\_0 which I assume can be considered as logical input 1 or 0\. I have output Logic\_Probe which I assume is also right and can be considered as output\. I have the same transistor NPN \(which is when powered to the base should allow the flow of the electricity\)\. Ground\, Source\(?\) I have \+5V they have Vcc in the EasyEDA it's under Supply Flag and I can't simulate with it so I really don't get it what's the point of this\. The only thing is different is I don't have resistors but are they needed here at all? Anyway, I really don't get you, so could you please clarify?

My Half-Adder is working but I HAVE TO HAVE source and ground, wtf... 

@stroibot, I'm sorry but you seem to expect to be able to construct and successfully run a simulation based on your own assumptions about the various elements and rules of simulation in EasyEDA. For example: * You have a 5V net flag. A net flag is a graphical element. It is not a voltage source. * You have no explicit resistors placed for R1 and R2 and nothing else that might that represent them in your simulation. * You have a bipolar transistor i.e. an analogue component and not a dedicated logic gate spice symbol. * You are using dedicated logic signal source and dedicated logic output state indicator elements instead of voltage source and voltage probe elements in a simulation schematic with an analogue bipolar transistor. You have already been advised that to successfully run simulations in EasyEDA, you need to read - and play with the examples in - the Simulation Tutorial, (3) in (2) in: [https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a](https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a)<br> <br> Everything that could be written here to help you to successfully run simulations in EasyEDA is already written in the Simulation Tutorial so please read it as it is unfair of you to expect people to spend time answering questions that are already adequately covered in the existing and readily accessible documentation to which you have already been referred. You may also wish to study this simulation to help you understand how to construct a simple bipolar transistor inverter stage: [https://easyeda.com/editor#mode=sim,id=3db9c58fad9b44d3ae30b2f8e825598a](https://easyeda.com/editor#mode=sim,id=3db9c58fad9b44d3ae30b2f8e825598a)

Well, I guess EasyEDA is not something what I was looking for

@stroibot, You may find a local installation of LTspiceXVII more to your liking. Alternatively there are pure logic simulation tools available such as: [https://circuitverse.org/about](https://circuitverse.org/about)<br> <br> and more: [https://www.techwareguide.com/free-online-logic-gate-simulator-tools/](https://www.techwareguide.com/free-online-logic-gate-simulator-tools/)