# Is it really possible to obtain a AC signal (voltage/current) from a pure DC signal?

As one can see that there are circuits in figure 1 which consists of a AC voltage source with $V= V_m sin(2\pi f t)$ ,a diode and a resistor.

Now, if I do $V_{o1}+V_{o2}$, I will get same bidirectional AC signal, IE. $V$

But if I do $V_{o1}-V_{o2}$, I will get a unidirectional AC which is also can be called as DC signal(?).

Now, I want to know that is it really possible to obtain an AC signal ( Voltage/current) from pure DC (IE $f=0$) input signal. If yes, what could be the circuitry in the question box of figure2?

• Have you heard of oscillators, multivibrators, voltage inverters and similar? Sep 14 '16 at 17:19
• @EugeneSh. Could you please tell me how they convert pure DC signal into AC signal ? If possible with its circuit diagram? Sep 14 '16 at 17:25
• He already told you. Search about sinusoidal oscillators. Sep 14 '16 at 17:27
• Take a look here for one example, though you better start with theory. Sep 14 '16 at 17:28
• In the old days they did this electromechanically: a DC motor driving an AC generator. Now we use electronics. There are many ways to do this. Since you're just learning about diodes, you're not ready for those schematics yet. If it was suddenly impossible to convert DC into AC almost all electronic devicees would stop working instantly !!! Sep 14 '16 at 17:47