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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.

Hope this helps
-Wil


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