i wouldnt draw more than a mA from a parallel port pin just to be safe---even tho you can obvisouly draw more.. if you are worried abot current, use a mosfet instead of a bjt and adjust accordingly.. im an EE student myself and i learned about jk and d flip flops in my 2nd year---in a digital logic class.. you will likely learn about it soon
ok, well the current design uses an opamp as a buffer (or comparator?) for the "on" signal. this doesn't work in testing, the test led stays on at ALL times. the only time it worked was when the signal was applied to the noninverting input, and nothing was connected to inverting, not even ground.
the "off" switch is done with an inverting buffer and works better than i had expected. for some reason tapping the switch turns the test led out and it will stay out for about a second even though the switch has been released.
the voltage on the parellel port is 3.3 volts right?
also, can you hook up opamps backwards? so far my testing points to "no"...
the "off" switch is done with an inverting buffer and works better than i had expected. for some reason tapping the switch turns the test led out and it will stay out for about a second even though the switch has been released.
the voltage on the parellel port is 3.3 volts right?
also, can you hook up opamps backwards? so far my testing points to "no"...
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