Can you still buy radio valves?
Many valves are still available. A good range is being manufactured again, and are available from dealers. Often though they are aimed more at the audio market. Many of these originate from the former Soviet Union, and the developing countries.
Are old radios valuable?
Valuation for vintage radios Some pre-battery powered radios from the 1920s and 1930s are valued according to their condition. Rare radio sets in good condition from these periods are the most valued items.
How does a radio valve work?
This is a common arrangement in valve radio receivers. A resistor is placed in series with the control grid (g1). This works in conjunction with the input capacitance of the valve to attenuate the high frequencies (above the audio range) to ensure stability.
When did Mullard stop making valves?
This photograph from our archives, shows the few staff which were left, when the very last valve came off the production line and the factory closed, in 1982.
What is a vacuum tube radio?
A vacuum tube, also called a valve in British English, is an electronic device used in many older model radios, television sets, and amplifiers to control electric current flow. The cathode is heated, as in a light bulb, so it will emit electrons.
What do Valves do in an old radio?
Later known as the Fleming valve, the oscillation valve was developed for the purpose of rectifying radio frequency current as the detector component of radio receiver circuits.
What do valves do in old radios?
A valve is an amplifier. Its output signal is much bigger than its input signal. So in principle a simple radio receiver could be made from a single valve with an aerial connected to its input and a set of headphones at its output.
Why did radios have valves?
The valve was useful as an electronic switch and its first use was in radio circuits detecting signals. The valve has two elements – a wire and a metal plate surrounded by a vacuum. The electricity flows between them.