- Apopka, Florida, United States
- Oct 29th
IET GenRad GR Model 1521-B Graphic Level Recorder produces a permanent ink record of the level of ac voltages, at frequencies from 7 cps to 200 kc. The trace, which is proportional to the logarithm of changes in input level, and hence linear in decibels, may be plotted as a function of time, on translucent chart paper. When the recorder is set up to drive the dial of an external oscillator, it automatically