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Table of Contents
Summary of Contents for QMC instruments ULN95
- Page 1 ULN95 Preamplifier Operating Manual Serial Number xxxx...
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Page 2: Table Of Contents
CONTENTS Introduction Packing List Preamplifier Operation Preparing the preamplifier Powering the preamplifier Power option a) Using an external power supply Power option b) Using the internal batteries Recharging the batteries Altering the detector bias Troubleshooting Contract Details and Guarantee... -
Page 3: Introduction
Introduction The ULN95 (Ultra Low Noise) preamplifier is a voltage mode low noise preamplifier designed for use with cooled detectors. It can be powered either from internal rechargeable batteries or from an external ±15V DC supply. Switchable gain options, a potentiometer bias supply control and full detector status monitoring are provided. -
Page 4: Packing List
Packing List The following items are included in this shipment. Please check the contents against this list and contact QMC Instruments Ltd as soon as possible if you suspect that any items are damaged or missing. ULN95 Preamplifier Ω bias resistor... -
Page 5: Preamplifier Operation
Preparing the preamplifier The preamplifier batteries have been disconnected for transit. Open the front of the ULN95 by unbolting the four bolts that hold the lid in place. The battery pack should be fixed in position as shown in Photo 1a, using the four nylon fixing screws. -
Page 6: Powering The Preamplifier
Photo 1b. Connecting the batteries Powering the preamplifier The ULN95 can be operated from the internal batteries or from an external power supply. External power is supplied via the 4-pin socket located at the top of the preamplifier control panel. The three isolated pins are used while the earth tag is not used. -
Page 7: Power Option B) Using The Internal Batteries
External supply switch-on procedure is as follows from the following initial settings: RECHARGE = OFF; POWER = EXT; INPUT = SHORTED; BIAS = OFF 1. Ensure that the power supply output voltages are set to 0V 2. Connect the power lead as shown in Photo 2 below. Plug the other end into the RECHARGE SOCKET 3. -
Page 8: Recharging The Batteries
TP1 and TP2. To set V adjust the multi-turn potentiometer VR1. V will have been set at QMC Instruments Ltd during testing but can be altered using the potentiometer VR1 and measured between TP1 and TP2. To measure I connect a... - Page 9 voltmeter across TP1 and TP3 and convert the measured voltage in mV to I /µA using the conversion factor 1mV/µA. V is measured by connecting a voltmeter across TP1 and TP4. The operating resistance of the detector can then be calculated from R .
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Page 10: Troubleshooting
Replacement battery packs can be obtained from RS. If problems are suspected with the ULN95 preamplifier there are some basic checks that can be carried out. Disconnect the ULN95 from the external supply and then open the box it by undoing the four bolts. Check the following: •... - Page 11 Figs. 1(a, b) below give typical input shorted noise of the ULN95 amplifier at a gain of x100 1200 1600 Frequency / Hz Fig. 5.1a. Typical preamplifier input shorted noise spectra -1/2 Amplifier gain = x100. Noise at 1kHz = 1.0nV.Hz...
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Page 12: Contract Details And Guarantee
Defective parts will be repaired or replaced on return to the final supplier at no cost, provided that failure is not due to misuse or mishandling after delivery. QMC Instruments Limited will assume no liability for loss of life or damage to property arising from the use or misuse of its products.