??? 02/12/05 10:54 Read: times |
#87197 - Saturation and Gain Responding to: ???'s previous message |
Refer to datasheet: http://www.fairchildsemi.com/ds/BD/BD236.pdf The magic 6A collector current is specified at a 300uS pulse with 1.5% duty cycle - not exactly what you'd see in a multiplexed display! Also refer to the gain Vs collector current graph. To saturate the transistor you need to provide enough base current. From a quick look at the graph, the gain would drop from about 100 to less than 10 at 6A. Thus you would have to feed the transistor (xistor) 600mA! This is why fets are a bit nicer to use - just give them enough gate volts - downside is the gate capacitance. It helps to read the datasheet closely. |