hello i have been having trouble working with bipolar transistor. i have been taking pulses that at less then 1us long and amplifying them with transistors. how ever if i have a bipolar transistor as part of my amplifier whether it is my inputs are as part of another stage the pulses always are outputted as a >1us time pulse that has been amplified. i have used the bipolar transistor in may ways to try to eliminate the problem. but they all have the same outcome. the output is always a fast rise and a slow drop which would indicated current flowing easier one way. so i use pnp and a npn to see if the shape would change but it does not. can anyone give me advice.