This is an instruction manual for the 2680M1-M7/2680M12-M14/2680M61-67/2681M1-M7/2685M1-M7 airborne charge amplifier. It introduces the features of the product, including adjustable gain, outputs, DC-DC converter, input power, optional filters, accessories, and applications.
The Endevco Model 2680 Series consists of solid-state airborne charge amplifiers designed for use with piezoelectric transducers. These epoxy-potted and hermetically sealed units feature a charge converter front end, an optional filter, a gain potentiometer, and a voltage amplifier to produce an output voltage proportional to the input charge. The series includes various configurations such as the basic Model 2680 with Viking connectors and the Model 2681 with a DC-to-DC converter, available in multiple gain ranges (M1 through M7, M12, and M14).
This manual provides instructions for inspecting and installing the device, performing pre-operation voltage insertion tests, and conducting operational checkouts including gain adjustment and amplitude linearity verification. It also details the theory of operation, gain adjustment procedures, and lists specific input/output characteristics for each model variant.
| Operating Voltage | 20 to 32 V dc (28 V typically) |
|---|---|
| Output Impedance | less than 50 Ω |
| Bias Output Voltage | +2.5 V dc ±3% |
| Maximum Output Voltage | approximately 0 to 5 v (±2.5 v pk) |
| Gain Potentiometer Resistance | 500 kΩ (±0.1%) |
The difference is the type of output connectors used and the addition of the DC-to-DC Converter in the Model 2681.
The gain is adjusted using a removable screw that provides access to a Gain Potentiometer located on the side of the case or connector end.
The output circuits are short-circuit proof and will withstand an indefinite short without damage.