TN90A Pointer VU Meter High-precision digital power meter head level indicator audio spectrum for speaker amplifiers

Description TN90A Pointer VU Meter High-precision digital power meter Head level indicator Audio spectrum for loudspeaker amplifiers Standard test conditions: Temperature 20 °C, relative humidity 70%. If no differences are observed in the test results, the test can also be performed under normal temperature and humidity conditions. Current sensitivity: The pointer scale ranges from zero to maximum (full scale deflection). The sensitivity is 960 µA ± 8%. Internal resistance: 650 Ω ± 10%. Insulation resistance: 500 V DC chassis and circuit voltage plus 50 mΩ or higher. Zero point determination: Use the standard position of the meter. The point where the pointer tip coincides with the center of the zero scale serves as the reference point for pointer and zero point overlap. The tolerance is ± 1 mm. Balancing: If the measuring instrument is tilted 90° forwards or backwards, the permissible deviation is ± 1 mm. Pointer jamming: If the full-scale deflection current suddenly triples the overcurrent and the current measurement sensitivity slowly decreases from half, the pointer returns to one-third of the scale value. Friction: When a current is applied to the meter and its slow increase or decrease to a specific value, the error tolerance of the reading point is ± 1 mm. Pointer movement direction: from left to right. Needle length: 44 ± 1 mm from the center line to the needle tip. Pointer width: 0.45 ± 0.05 mm. Meter operating direction: vertical. Operating temperature range: -10 °C to +60 °C, relative humidity 35 to 85%. Storage temperature range: -20 °C to +60 °C, relative humidity 35 to 85%. Do not expose the meter to direct sunlight and store it in its packaging to prevent sunlight from entering. Welding conditions: The leads are immersed in approximately 3 mm thick tinplate for 3.5 seconds at 230 °C and remain in this test. In perfect condition. Soldering temperature: The soldering iron temperature is maintained at 350 °C. Contact with the connector is made for 3.5 seconds, with the front of the connector being brought into contact with the soldering iron to a depth of approximately 3 mm. This test also passed without any problems. Antistatic: The surface of the transparent cover plate is checked with a dry nylon cloth in the same direction.