| Home |
| Search |
| Today's Posts |
|
#3
December 9th 06, 07:16 PM
posted to rec.radio.amateur.boatanchors
|
|||
|
|||
How does that meter work?
but a lot of instruments use what are called taut-band suspension. The meter
coil or vane and pointer are suspended on a flat ribbon running along the axis of rotation and fastened at the ends. The band acts as both support for the moving mechanism and as the restoring spring. It is essentially a torsion spring. The advantage of this system is that it eliminates the bearings along with the friction and hysterisis they cause. Taut-band meters have very good repeatability and can be very accurately calibrated. Hewlett-Packard began to use taut-band meters in their instruments along around the early 1960's and they became common around that time. Taut-band meters do have zero-adjustments but they may be internal. The damping of any meter is a matter of the back EMF of the meter. No meter running open circuit will be well damped. It may be that the testing circuit does not have low enough resistance to damp the meter. If you rotate the meter open circuit the pointer wil move around a lot. If you short the terminals it will barely move at all. Richard Knoppow Los Angeles, CA, USA Hi Dick, in taut band meters the taut band replaces the torsion springs. But the Hallicrafters meter has a rigid axis (not taut band), and has neither torsion springs nor a moving coil, so it must work on a different principle. Thank for the advice and 73 Tony I0JX the Hallicrafters |
| Thread Tools | Search this Thread |
| Display Modes | |
|
|
Similar Threads
|
||||
| Thread | Forum | |||
| If you had to use CW to save someone's life, would that person die? | Policy | |||
| Electromagnetic Radiation | General | |||
| Electromagnetic Radiation | Policy | |||
| SWR meter kaput? | Antenna | |||
Threaded Mode
