Tina - TI 

Tina-Ti is a utility meant to help electronic engineers and students in designing circuits with the possibility to test and troubleshoot them. The number or devices and nodes that can be included in a circuit is not limited.

The user-friendly interface makes it easy to find the necessary tools for designing a circuit. There are several switches, meters, sources, semiconductors and spice macros to choose from. When evaluating a circuit in function mode, a multimeter, oscilloscope, a signal analyzer and others can also be used.

When a component is right-clicked, a menu will appear offering options such as to rotate the component, to connect it to other components using the "wire" tool or to change its properties. For example, when you choose to change the properties of a resistor, parameters such as resistance, power, temperature and others can be modified. When the "Edit Symbol" option is picked, the shape of symbols can be changed. Several kinds of analyses can be performed, such as AC, DC, Fourier or noise analysis.

All in all, Tina-Ti offers a wide set of possibilities for designing a circuit and simulating its functioning.