Number of windings for 120-V household circuit?

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To determine the number of windings for a 6 V output from a transformer connected to a 120-V household circuit, the turns ratio formula V1/V2 = N1/N2 is used. Given that the primary coil has 240 windings (N1), the calculation shows that N2 equals 12 windings for the secondary coil. This is confirmed by the relationship between the voltage and the number of windings, indicating that the transformer is a step-down type. The explanation clarified the concept for the inquirer, leading to a better understanding of transformer operation. The correct number of windings for the secondary coil is thus 12.
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A model train requires 6 V to operate. If the primary coil of its transformer has 240 windings, how many windings should the secondary have if the primary is connected to a 120-V household circuit?


V1/V2 = N1/N2



my teacher went over this with the class, and said that N2= 6V/120V(240), so it equals 12. I don't get how he got that answer. Can someone help me to understand please?
 
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He is correct. This type of transformer is sometimes called a stepdown transformer because it transforms a big voltage to a smaller one. The turns ratio equals the desired voltage ratio, so
n2/240 = 6/120
and n2=12 as claimed.
 
I see. Thank you. For some reason, how you wrote it, it clicked in my head.
 
You're welcome!
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
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