Is it possible to apply a voltage to the secondary side of a transformer and call it the primary?

 

Yes, but voltage/current/power limits must still be observed.

 

Are you asking for the circuit like this ?
-- 12V to 120V DC DC converter.

 

Are you asking for the circuit like this ?
-- 12V to 120V DC DC converter.

No! I was asking because I'm watching this video on udemy and the instructor said u can apply a voltage to the secondary and call it the primary

 

Yes, but voltage/current/power limits must still be observed.

Ahh! Do u mean the current,power and voltage on the secondary side?

 

Normal transformers are completely bidirectional, so the labels of "primary" and "secondary" are arbitrary as long as all voltage and current limits are observed.

 

Normal transformers are completely bidirectional, so the labels of "primary" and "secondary" are arbitrary as long as all voltage and current limits are observed.

Okay, thank u so much for your input

 

No! I was asking because I'm watching this video on udemy and the instructor said u can apply a voltage to the secondary and call it the primary

What video, links?
Do you know what I means about the circuit, the circuit shown that you can use an AC120v to 9-0-9 Vac transformer and reverse it just let the secondary coil (9-0-9 Vac) as the primary coil (AC120V)and the primary coil (AC120V) as the secondary coil (9-0-9 Vac).

 

Most small transformers do not mind, but one of the larger manuf such as Hammond Transformers have a caution
"Hammond Systems, strongly discourages back-feeding Industrial Control transformers, and Distribution transformers smaller than 6kVA.
Due to the use of compensated winding's in these products, the resulting voltage will vary from the rating with as much as 10%.
Max.