Flashtubes versus flashbulbs

When I was young cameras a casual user could easily afford all used single use flashbulbs. I remember seeing reusable flashes, but they were expensive. Now single-use cameras have flashtubes, as do digital cameras. Why have they gotten so much cheaper? Is xenon cheaper now, did they develop a substitute, or is it just that they developed much cheaper circuits and/or manufacturing methods?

This, for the most part.

Freeing the consumer from having to carry and dispose of flashbulbs was a big concern, too.

not only cheaper circuits and methods, components for this were made smaller so that the flash could fit into a device.

Many cameras were only mechanical (no batteries), which flashbulbs didn’t need batteries. When cameras started to include more electronics then you had the power for the flashtubes.

Not really.
The percussive flashbulb was a fairly late invention, designed by Kodak for the Instamatic. Before that, all flashbulbs were electrically fired, usually by batteries in the handle of the flashgun. Xenon flashes (“strobes”) were expensive at the outset for the same reason any new electronic device is - it’s always expensive to turn a new technology into a mass-produced product. The flash circuit in modern cameras has been reduced to a bare handful of parts, and the flashtube itself is a mass-produced item. Soon, those will be obsoleted by HB LEDs.

Yeah, off the top of my head, in order to fire a xenon flash tube, you need a fairly high voltage. You get this using a transformer, and to use the transformer, you have to convert the DC in the batteries into AC (which is why electronic flashes have the characteristic whine). The voltage is stored in a capacitor and then released when you hit the shutter. For this last step, you need a semiconductor that can handle high voltages (although maybe you can use a mechanical switch).

If you add circuitry to sense the amount of light released and shut off the flash when the exposure is sufficient, things get more complicated, but the basic circuit is pretty simple.

Anyway, none of this circuitry is particularly complex, but particularly in the early days of transistors they wouldn’t have been dirt cheap either. By the mid-70’s, simple flash units were reasonably affordable.

However another reason why cheap cameras probably didn’t come with built-in flashes was that the production of consumable flash bulbs/flash cubes was big business for the camera companies. When you can flash bulbs that cost as much as the film, there’s not going to be much motivation to innovate. Manufacturers probably only switched to built-in flashes after third party manufacturers devised plug-in flash units that replaced the bulbs.

Too bad, in a way. Today’s kids will never know the joy of taking a nine-volt battery and blinding yourself with a flash bulb, burning your hand in the process.

Another factor to consider.

Early cameras needed much light due to slower/grainer film and slower camera lenses. As time progressed you needed less and less light to take a photo.

A flashbulb puts out a lot more light than a flash (particularly the early models).

As flashes, lenses, and film got better eventually the flash became as or more practical than the flashbulb as a workable light source.