Radiation Symbol

FC's Geiger Counter Circuits

Support this site by buying a CirKits kit.

Solar Charge Controller Dark Activated Switch Low Voltage Disconnect Battery Voltage Monitor


Radioactivity is a topic that gets a lot of coverage in the media. It is something that we cannot see, smell, or hear. The same can be said for most forms of electricity and electromagnetic radiation. Tools such as volt/amp meters and oscilloscopes give us a view into the world of electricity, a geiger counter allows real-world radioactivity to be measured in a similar fashion. There is much folklore, information, and mis-information online concerning radioactivity. Some real-world experience can help to demystify the properties of natural and man-made radioactive materials.

A practical use for a geiger counter is to locate low level radioactive sources in and around the household in order to move them from your living space. Examples of radioactive materials that can be found inside the house include rock/mineral colections, certain pottery glazes, gas lantern mantles, antique watch/radio dials, certain welding rods, and radon gas. Green depression glass antiques and some transmitting vacuum tubes contain uranium.

Common household smoke detectors manufactured between the early 1960s and the early 2000s typically contained a tiny piece of radioactive americium, which mainly emits alpha particles. Very little alpha radiation eminates from this ionization type of detector because it is blocked by a metal shield and the smoke detector's plastic case. The life-saving capabilities of these smoke detectors far outweighed any negative effects of their small amount of radioactive material. That said, newer smoke detector technologies have shifted to the use of optical detection methods due to its higher sensitivity. For more information, see the Wikipedia article on smoke detectors.

Keep in mind there is, and has always been, a fair amount of normal background radiation from naturally ocurring radioactive minerals in the ground and the radon gas produced by the decay of the same minerals. Above-ground atomic testing in past years has increased the background radiation levels somewhat, but this is mostly a concern for people living close to nuclear test sites.

Geiger Counter Circuitry

Here are some projects that can improve and extend the capabilities of readily available surplus geiger counters such as the Victoreen CDV-700.

Useful Links

Back to FC's Electronics Circuits page.

Email Me