(no subject)

Since the temperature on the stair landing at work was 58F, work was closed yesterday so I got up later. Too late for the dog, who peed on the floor in front of our front door as I got my coat on. We took a quick dash outside anyway and I gave him breakfast. Just after he ate but before I could give him his seizure medicine, he started seizing. At home, I realized that I couldn't log into Dreamwidth or Livejournal because I'd updated the passwords and forgotten to copy the database of my password manager to bring home. One of *those* days, huh?

It was pretty decent all-in-all though. I got a bunch of cleaning done and was on the library chat system to answer questions. (There weren't any.)

I'm back at work today, and this afternoon Erik will be coming to visit so we can look at some of his pictures from a behind the scenes trip he got to do at Fermilab. If he can get his car out of the snow...

(no subject)

I've spent hours on this circuit and cannot figure it out.

It ought to be really simple, right? Nine volt positive rail is the source voltage for an LM386 audio amplifier chip. An AC signal is introduced at TP2. That signal goes through a 100Ω resistor, then is coupled through a small cap to a 50kΩ pot that serves as a voltage divider to ground. The attenuated signal goes through another cap (Why 2? I don't quite understand. Posi said it's for tuning the circuit.) to the non-inverting input of the amplifier. The amplifier's inverting input is tied to ground.

The lowest my frequency generator seems to go is about 2 volts peak-to-peak, so that's what I'm introducing at TP2. Probing the input line after the caps with my scope shows that they are stripping out the DC offset from the generator so it's just a sine(ish) wave centered on 0 volts. But my VOM says that the LM386 puts out 15 volts AC no matter how I set the pot. The speaker makes a low hum when I first turn the circuit on, and if I raise the volume (the pot voltage divider) even just a little bit, it gets really loud.

The pot should be able to attenuate the input signal from 2 volts PtoP down to basically 0. Stupid thing. More troubleshooting to do. Maybe I connected something wrong.

(no subject)

I saw the Super Bowl mentioned today and remembered how last year I wanted to watch the Puppy Bowl but do not have any way to see it at home. I was going to get online and see if I could convince anyone to host a Puppy Bowl party whenever the Super Bowl happens. We could get a bunch of food together and watch puppies being cute! Then I found that it's this weekend, so I guess the notice is a little short. Maybe next year.