Small Circuits Revival - XXL Escaped from the Suggestions Box

摘要

During the past six months we've been publishing a Small Circuit every week on our website and in our newsletter. The circuit can be assembled without any special, exotic parts and with a normal soldering iron on breadboard. Now it's a circuit 'from the old days' and then a recent entry from a reader, or an idea from our lab. These circuits are discussed on the website - sometimes controversially - and that's exactly our aim: to stimulate discussions, experiments and readers' own discoveries! Here is a selection from the first 26 episodes. That is why this circuit is provided with two antenna connections. When connected via the 12 pF capacitor, it is loosely coupled and the damping is small. By contrast, the direct connection is (also) suitable for very short antennas mianly because a longer antenna also radiates RF energy which damps the oscillator circuit. When adjusted correctly, an audion is extremely sensitive; in the early days of radio technology these types of receivers were part of the standard equipment. Even with weak transmitters, distances of up to a thousand miles could be covered.