Well, today was kind of discouraging. Here’s the new autofade lamp test circuit, upgraded:
And here’s the key:
A: I replaced the red LED with a flashlight lamp. The soldering operation was successful and the light is bright enough.
B: I upgraded the capacitor from 1000 microfarads to 3300.
C: The transistor got hot, so I swapped out the 2N3904 to a 2N4401.
And . . . it doesn’t work.
When the LED is swapped back in, the circuit works fine, but there’s not enough base current to amplify the collector current enough to light the lamp. And I do mean that I don’t even see a glimmer.
Where to now? Try a power transistor, try two transistors in piggy-back, try different resistance values. I’m sure there’s a way to make this work, but we’ll probably put it aside for a while because I want to spend some time brainstorming ideas for other future products and how to market them.
Maybe I should draw something in Sketchup. That’s often relaxing.