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hey guys trying to get this resistor to act as a switch so when power comes on, it completes another circuit.. what wrong with it?

https://www.circuitlab.com/circuit/4knhh6/switch/

Is this what you're trying to do?

well pretty much i have two leads coming in from another circuit. ones the positive and ones the negative. when something happens in the other circuit it sends out 3v. when this voltage is sent out, i want it to complete another circuit. what a relay would do. anyways is this what it is doing? and could you modify it for a npn transistor? and whats up with the little ground thing there?

@microzee,

" ... whats up with the little ground thing there?"

CL is not just a way to draw passive circuit diagrams.

It is also a simulation tool.

The circuit above is an active simulation circuit.

Please read:

https://www.circuitlab.com/docs/

and

https://www.circuitlab.com/docs/faq/

" ... what a relay would do. anyways is this what it is doing?"

If you open the circuit in the CL editor and follow the instructions on the diagram, you'll see how the circuit works.

However, bear in mind that this is an example. It is not a practical circuit that you can just build and expect to work.

" ... could you modify it for a npn transistor?"

Yes but it would probably be better to use an N channel MOSFET. See CL documentation about device models and note that the choice of components in CL is very limited even after allowing for being able to edit transistor parameters.

Please also consider that if you are asking for someone to spend their time designing you a practical circuit so that it works reliably in the real world then you have to be prepared to spend your time to specify clearly:

i) what you want the circuit to do;

and

ii) what the real world that it has to operate in actually looks like.

Simply saying:

" ... when something happens in the other circuit it sends out 3v. when this voltage is sent out, i want it to complete another circuit. what a relay would do."

is not enough to design a circuit from. You need to provide more information.

" ... in the other circuit it sends out 3v."

Source resistance of the 3V source: high? low? low at 3V, high when not 3V?

High level voltage and tolerances of the 3V source?

Low level voltage and tolerances of the 3V source?

How much or how little current are you allowed - or do you want - to draw from the 3V source?

How long is this 3V applied for?

" ... i want it to complete another circuit. what a relay would do."

How far from the 3V source is the switch and/or load?

Do you want the switch to open again before the 3V is removed?

What voltage that has to be switched?

How much current has to be switched?

Resistance of the Nichrome wire when cold?

Resistance of the Nichrome wire when hot?

Is short circuit protection required on the control and/or the load port?

Is reverse voltage protection required on the control and/or the load port?

What conditions does it have to operate in: outdoor use? temperature range? humidity range? dusty? oily? lots of vibration?

Possible interference from an RC transmitter?

If so what frequency range?

:)