PYE SCALAMP FLUXMETER, 1950's

An internal lamp sends a beam to a mirror attached to the movement of the meter; the beam is then reflected onto the screen as a vertical line. This makes the instrument very sensitive. The use of this instrument is to measure magnetic field, and it is known as a "Fluxmeter". A coil is connected to the input terminals and this can be used to measure changes in field strength. This technique pre-dates measurement of magnetic field by nuclear magnetic resonance which is a technique used in archaeological searches.

Donated by John Barnes

Your comments:

• I used one of these to measure the strength of a largish electromagnet in the early 1960s. It was used in conjunction with a small coil attached to a piece of elastic - you held the coil in the magnet gap, waited for the meter to settle, stretched the elastic and released the coil. This caused a pulse of induced current and you observed the maximum ballistic deflection of the light spot. I'm afraid I've totally forgotten how the reading was converted to field strength, but it was a fairly routine procedure at the time.
  .......... Mike McCann, London, England, 13th of December 2015
  
  
• We still use one at our school, divine apparatus!
  .......... Andy Goloskof, Tewkesbury, 3rd of March 2015
  
  
• I used one of these a couple of times at Barnet College circa 1969 when doing day release (from STC Ltd) ONC electrical engineering there. The movement wasn't damped and ballistic (no return spring). To set up, you centred the spirit level bubble and after allowing the light beam to settle, carefully turned the top knob to zero it. I recall a lab experiment where you had to plot a family of flux density (B) versus magnetising force (H) curves with it for a selection of grades of iron cores.
  .......... Robert Long, Llanerchymedd Anglesey, 5th of July 2013
  
  

A1484