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How fast can a transistor switch on and off?
Feng and Hafez developed a transistor less than half a millionth of a metre long, with a maximum operating speed of 604 GHz, meaning it can carry out 604 billion operations every second.
What is the max CPU speed?
As of 2011, the Guinness World Record for the highest CPU clock rate is 8.42938 GHz on an AMD FX-8150 Bulldozer-based chip. As of 2012, the CPU-Z record for the highest CPU clock rate is 8.79433 GHz on an AMD FX-8350 Piledriver-based chip.
How is transistor rise time related to VBE?
It would be nice if there was a mathematical way to relate the transistor rise time, fall time, t-on time with Vbe and the frequency of the switching signal. For predictable switching speeds, you must quickly inject currents into the base to turn on, and quickly remove current from the base to turn off. Use speedup caps across the base resistor.
Why does the rise time of a transistor decrease?
As you can see, the collector current decreases a lot by increasing the frequency. My guess: by increasing the frequency, the period of Ib get smaller and smaller. Eventually the rise time of the transistor may be longer than the dutycycle, hence there will not be a t o n time. This is what triggered my original question.
What is the current gain of a Darlington transistor?
For example, if the first input transistor has a current gain of 100 and the second switching transistor has a current gain of 50 then the total current gain will be 100 * 50 = 5000. So for example, if our load current from above is 200mA, then the darlington base current is only 200mA/5000 = 40uA.
Why are multiple transistors used in a bipolar transistor?
Sometimes the DC current gain of the bipolar transistor is too low to directly switch the load current or voltage, so multiple switching transistors are used. Here, one small input transistor is used to switch “ON” or “OFF” a much larger current handling output transistor.