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[DPRG] Queries about the McManis H bridge
Subject: [DPRG] Queries about the McManis H bridge
From: Vimal Shankar
vimalsshankar at yahoo.com
Date: Sat Oct 7 15:48:10 CDT 2006
I have a few queries about the McManis's bridge :
1. In the explanation at :
http://www.mcmanis.com/chuck/robotics/tutorial/h-bridge/bjt-impl.html
Can someone please explain to me why the 10k pull-up
resistor insures that the transistor is "off" (or not
sourcing any current) when the switch is open.
Same for "In the sink circuit the 10K resistor
connects the base of the transistor to ground, which
forces the transistor off when the switch is open."
As far as I know, the transistors will turn on only
when the base is correctly biased. It will ALWAYS be
"switched off" otherwise - so why the pullup / pull
down resistors ?
2. Can I use the 1N4001 in place of the 1N4936 ?
Also, how do I know the specs of the inbuilt
freewheeling diodes in the TIP122/127 ?
3. I am using the TIP122/127 in place of the
TIP102/107. Will it matter much (I promise to stay
within the amperage mentioned in the specs of the
TIP122/127)
4. What about using the CNY17-2 inplace of the
menioned optoisolators ?
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