How do I use Thevenin's theorem to determine the values of the Thevenin equivalent on the right? Vth=? Rth=?

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mariloucortez eNotes educator| Certified Educator

RTH is the resistance measured at terminals with all voltage sources replaced by short circuits and all current sources replaced by open circuits. Since in this case you only have a voltage source, you just short that out.

Shorting the source the, resistances are in parallel connection.
`R_1 = 15 ohms` 
`R_2 = 30 ohms` 
`V = 15 V`

`RTH = (R_1(R_2))/(R_1+R_2)`

`RTH = (15*30)/(15+30)`

`RTH = 450/45`

`RTH = 10 ohms`

VTH is voltage seen at the terminals. You can use voltage divider:

`VTH = (V * R_2)/(R_1+R_2)`

`VTH = (15*30)/(15+30)`

`VTH = 450/45`

`VTH = 10 V`

Thus, RTH = 10 ohms and VTH = 10 volts.