The purpose of an H bridge is to steer the current through the motor coil in both directions. In one of the directions the motor moves in the clockwise direction, and in the other direction it moves counter clockwise.
the two emitter transistor, or tetrode transistor was an early type used for higher frequencies than the point contact transistors of the time. google up 3n22 transistor.
cliff
telephone company equipment and military mostly. they worked to 15 mhz according to one source on the net. that is faster than most other transistors available back then.
Yes they are used in high frequency circuits it says , but what does having two emitters do? Is the 3n22 used as a switch or ampilifer? It seems that it has to have a high state on both emitters at the same,e time for it to be switched on or to amplify? If one of the emitter signals is a low state , the 3n22 will not operate?
if you check the sources on the net, you see that it is an amplifier, the other emitter was used as a bias to increase the electron mobility to inrease hrequency of operation. back in the point contact transistor days, not very many worked as high in frequency as the am broadcast band, so they were trying things to improve frequency.
I'm new to understand about how transistors are different depending on frequency? So each transistor has a range of what frequenecys it can amplify or not or their will be a roll off of gain? What determines the frequency of a transistor?
