timhunkin/marconi hut circuits exhibition

THE HUT This hut is claimed to be the site of the first radio broadcast, by Marconi employees (see marconi figures). It is now part of Chelmsford's industrial museum at Sandford Mill. The commission was to make a set of exhibits to explain the basics of electricity. These are a few of them		ELECTRICITY, HEAT AND MAGNETISM The idea was to show that electricity flowing through a circuit makes the wire magnetic and hot. We used a car battery so the effect would be easily noticable. Although we included various safety devices, the red hot wire was thought to be too dangerous so this exhibit is now run as a demonstration.

SIMPLE RADIO RECEIVER This is just a crystal radio, with the aerial run outside the building. Making it robust enough to last, lost some the magic of crystal radios for me. A length of wire, a germanium diode and a crystal earpiece is all that's needed. I still think its extraordinary that a crystal radio needs no battery - that the radio energy in the air is strong enough to pick up stations thousands of miles away.		BICYCLE POWER The idea is to connect a circuit all round the walls of the hut.

voice print.jpg (8407 bytes)

VOICE PRINT
Speak into the microphone, watch the electrical waves from your voice on the oscilloscope, and then press the button to get a voice print. This was made by Will Jackson, using a sensitive medical recording unit I'd bought in a car boot sale.