This manual covers the operation, calibration, circuit description, and specifications for the SR445 Fast Preamplifier, a four-channel DC coupled amplifier.
The Model SR445 Fast Preamplifier contains four wide bandwidth, DC coupled amplifiers designed to be used independently or cascaded to provide gains of 5, 25, and 125. It is ideal for amplifying outputs of fast photomultiplier tubes and photodiodes, featuring a rise time of 1.2 ns and a bandwidth of DC to 300 MHz.
The document provides detailed instructions on operation, including how to select input impedance and cascade channels. It also covers troubleshooting procedures, calibration steps for input and output offsets, circuit descriptions, overload behavior, line voltage selection, and a complete parts list.
| Bandwidth | DC to 300 MHz (-3 dB) |
|---|---|
| Rise/Fall Time | 1.2 ns |
| Voltage Gain | 5.0 per channel |
| Operating Range | inputs ±200 mV, outputs ±1.0 V |
| Noise | <50 µV rms referenced to the input |
| Power | 16W, 100/120/ 220/240 VAC, 50/60 Hz |
The maximum input voltage is 8 mV when three channels are cascaded to provide a gain of 125.
Disconnect the line cord, remove the fuse module, pull out the voltage selection card, rotate the plastic indicator to the correct voltage, and reinstall the components.
Allow the unit to warm up for at least 30 minutes, connect a voltmeter to the input, and adjust the pot at the front hole to 0.0 V ±10 µV.