I don't have a dynamo.
50 years ago, I did have a dynamo. It worked by friction against the front tire, and it meant I could have a feeble orangey light at the front, which an oncoming car would have trouble distinguishing from a glow-worm, and a dim ruddy glow at the back about as bright as a warm poker.
Today, I have a head torch that illuminates the track for several yards ahead and which would blind any oncoming motorist if I didn't have it dipped. And a rear lamp that shines like Betelgeuse, flashes like a pulsar and announces to anything behind me "HERE IS A BIKE".