This is a very common circuit in the days of xenon flashes for cameras. This is from a Radio Electronics magazine from November 1965. It uses an SCR and has manual triggering.
This circuit was found in old documentation but uses components that are still common. The circuit...
This transmitter kicks in when the microphone picks up sound. This sound then modulates the signal...
In the figure we have the way to connect an LED on the output of a power source to indicate the...