DoCircuits : Online Simulator (Must Try)
You can go to official website #-Link-Snipped-# & create an id.A single login allows to create infinite circuits & by clicking on "Launch Virtual Labs" you can save these circuits on the cloud so it can be accessed from anywhere.You can even share the circuits with your other users.
You can create & edit circuit without login, but to save & share the circuit the login is compulsory.
Alternative : There's also an offline version available at Rs.1000 for year's license.