prototyped with components

Prototyped the barn door tracker circuit on the Maxitronix Electronic Lab. Used all the provided and cobbled electronic parts, except for the switches. Didn't seem to work initially. No red LED. Motor not turning. Started to debug. Something downstream? Grabbed the digital multimeter.

Something was not right. Input volts checked out OK: 9.0 volts. Volts at the north-south switch showed high initially, 8 volts. Then 1 or 2. Oh. The momentary switch on the lab was bad. Shorted it. Tested again. Smooth now. But never went really low, like to 1 or 2. Minimum was 3. Checked the output of the N-S switch. Saw the polarity flip. Connected the motor. It turned. Looked too fast.

Fired up the stopwatch. Was not surprised to see RPMs twice as fast.

§

I can see the 150 ohm resistor is used in this test.