Name: Mike D.
Status: Student
Age: 20s
Location: N/A
Country: N/A
Date: Around 2001
Question:
Why are resistors used if they dissipate energy? Isn't
there a better way to design a circuit?
Replies:
Resistors perform many functions in an electrical circuit: 1. The
dissipation of electrical energy may be exactly what is desired, as in the
case of incandescent lights, and electric heaters. 2. It may be necessary to
know/control/vary the electrical current in a circuit. This is easily done
with a resistor and Ohm's Law V(voltage)= i(current)xR(resistance). 3. It
may be desired to have resistances that cannot be controlled, e.g.
resistance due to connecting wires of varying lengths from circuit be
negligible. This can be done by using a ballast resistor. The alternative of
using superconducting circuit wires in not practical in most cases. 4. It
may be desired to divide an electric current into several branches. This is
done by using resistors in parallel. 5. It may be desired to have an
alternating current curcuit that has a resonant frequency response. This is
done by using combinations of resistors, capacitors, and induction coils.
The list is long.
There may be alternative ways of designing circuits without resistors, but
it's hard to see how to do that as effectively and cheaply as a resistor.
Vince Calder
We have many fundamental components besides for the
resistor. Chips can replace larger circuits by using
transistors and such, and avoiding bulkier components
such as resistors. However, resistors are cheap.
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