1521-B
The General Radio 1521-B Graphic Level Recorder was introduced in Catalog S (1965) and remained available through Catalog 1978.
The Type 1521-B Graphic Level Recorder provides a permanent record of AC voltage versus time. With the addition of the 1521-P10 Drive Unit, the chart paper feed is now synchronized with the paired instrument. Is essentially converts the recorder from AC voltage versus time to AC voltage versus frequency. Some examples of this are the Type 1911 Recording Sound and Vibration System and the Type 1640-A Slotted Line Recorder system, and 1910 Recording Wave Analyzer.
The response to the input AC voltage is logarithmic so its linear in decibels. Using the supplied 40 dB potentiometer and four inch chart paper, travel of the pen is 10 dB per inch. Other potentiometers are available, the Type 1521-P1 20 dB and the Type 1521-P3 80 dB. A special potentiometer for DC recording is available as the Type 1521-P4. These potentiometers are part of the feedback circuit that position the pen, the pen being the wiper for the potentiometer. The built in attenuator adds additional attenuation to the potentiometer.
A list of accessories for the 1521-A include high and low speed motors, custom chart paper, and drive links for specific GR instruments.
Specifications
- Recording Range: 40 dB full scale with standard potentiometer
- Frequency Range: 7 Hz to 200 kHz
- Maximum Input Voltage: 100 V AC
- Input Attenuator: 60 dB in 10 dB steps
- Input Impedance: 10,000 Ω for AC level recording; 1000 Ω for DC
