Editing Dosimeter (section)

====Geiger tube dosimeter====
These use a conventional [[Geiger–Müller tube]], typically a ZP1301 or similar energy-compensated tube, requiring between 600 and 700V and pulse detection components. The display on most is a bubble or miniature LCD type with 4 digits and a discrete counter [[integrated chip]] such as 74C925/6.{{Citation needed|date=July 2023}} LED units usually have a button to turn the display on and off for longer battery life, and an infrared emitter for count verification and calibration.
The voltage is derived from a separate pinned or wire-ended module that often uses a unijunction transistor driving a small step-up coil and multiplier stage. While expensive, it is reliable over time and especially in high-radiation environments, sharing this trait with tunnel diodes, though the encapsulants, inductors and capacitors have been known to break down internally over time.{{Citation needed|date=July 2023}}
These have the disadvantage that the stored dose in [[becquerels]] or [[microsieverts]] is volatile and vanishes if the power supply is disconnected, though there can be a low-leakage capacitor to preserve the memory for short periods without a battery. Because of this, most units use long-life batteries and high-quality contacts. Recently-designed units log dose over time to non-volatile memory, such as a 24C256 chip so it may be read out via a serial port.