Context: Providing sufficient base drive current is a key problem in the use of bipolar transistors as switches. The transistor provides current gain, allowing a relatively large current in the collector to be switched by a much smaller current into the base terminal. The ratio of these currents varies depending on the type of transistor, and even for a particular type, varies depending on the collector current. In the example light-switch circuit shown, the resistor is chosen to provide enough base current to ensure the transistor will be saturated.

Question: What is a major problem with using bipolar transistors as switches?
Answer: Providing sufficient base drive current

Question: What does the transistor provide?
Answer: current gain

Question: What determines the current ratio in transistors?
Answer: the type of transistor

Question: If the type of transistor is the same what determines the current ratio?
Answer: collector current

Question: What controls how much gain a transistor provides?
Answer: Unanswerable

Question: How much current is needed to saturate a light-switch?
Answer: Unanswerable

Question: What determines how much collector current there is?
Answer: Unanswerable

Question: What fluctuates the most in a transistor?
Answer: Unanswerable