Measures counting rates up to 107 counts/s
18 full-scale meter ranges from 25 counts/s to 107 counts/s
Fast, medium, and slow response selections offer <1%, <3%, or <10% standard deviation in the measurement
Fast response circuit permits settling to 1% precision in a fraction of the normal time
Positive and negative inputs
Adjustable positive input discriminator
Flexible analog output for strip chart recorders

ORTEC Model 661 Rate Meter measures the counting rate of randomly arriving pulses, or the frequency of periodic signals in the range of 0 to 107 counts/s (0 to 10 MHz). This range of counting rates is covered with 18 different scales. The scales are arranged in a 25, 50, 100 sequence from 25 counts/s to 107 counts/s full scale.

Parameter Name	Parameter Value
Measured value	rate
Display	direct-reading
Type	panel-mount
Other characteristics	precision