Model 1900
Impedance Matching Transformer
The model 1900 low-noise impedance matching transformer is a versatile device for matching sources with impedances in the range from less than 50 mW to greater than 500 W to measuring instruments with high input impedance and offers two turns ratios of 1:100 or 1:1000. The frequency response depends on both the turns ratio and the source impedance, but under optimum conditions will be essentially flat from below 0.1 Hz to above 2 kHz. The unit is supplied with a special low-noise coaxial cable fitted with two BNC plugs to connect its output to the following instrument.

Model 5113
Low-Noise Voltage Preamplifier
The model 5113 is a high performance, low noise voltage preamplifier with continuously adjustable gain and optional high, low or bandpass filtering. Its input can be configured for either single-ended or true differential operation with either DC or AC coupling, and its output will deliver up to 2 V peak to peak into a 50 W load.

Model 5182
Current Sensitive Preamplifier
The model 5182 is a current-to-voltage preamplifier of low noise and low input impedance designed to amplify the extremely low currents encountered in such areas as photometry and semiconductor research. It has four standard conversion factors but in addition includes a special low-noise mode on the highest gain position for even better low current measurement capability. The unit features two outputs, allowing both the AC and DC components of the input signal to be independently monitored, so that, for example, in a PMT application the bias current can be measured separately from the signal current.

Model 5183
Nanovolt Preamplifier
The model 5183 is a high input impedance, AC coupled voltage preamplifier which features a very low noise input stage. It has a frequency response from 0.5 Hz to 1 MHz and a fixed gain of x1000 (60 dB) and incorporates a special pseudo-differential input stage that can be floated to give the ground loop immunity normally associated with differential inputs but without the associated noise penalty. It can be powered from its own internally housed (alkaline) batteries, an external low voltage supply (±15 V or ±18 V) or from the model PS0108 remote line power supply (optional extra).

Model 5184
Ultra Low-Noise Voltage Preamplifier
The model 5184 is a medium input impedance, AC-coupled, voltage preamplifier which features an ultra low-noise input stage. It has a frequency response from 0.5 Hz to 1 MHz and a fixed gain of x1000 (60 dB) and incorporates a special pseudo-differential input stage that can be floated to give the ground loop immunity normally associated with differential inputs but without the associated noise penalty. It can be powered from its own internally housed (alkaline) batteries, an external low voltage supply (±15 V or ±18 V) or from the model PS0108 remote line power supply (optional extra).

Model 5185
Wideband Preamplifier
The model 5185 is a wideband voltage preamplifier with a frequency response from DC to 200 MHz and switchable gain settings of x10 (20 dB) or x100 (40 dB). It has a selectable input impedance of 50 W or 1 MW and a DC offset facility. A ground switch allows the input signal to be isolated from the output and an adjustable offset facility allows a DC offset on the input signal to be subtracted before it reaches the amplifier output. An overload detector is also provided.

Model 5186
Differential Voltage Preamplifier
The model 5186 is a high input impedance, low-noise, AC-coupled, voltage preamplifier which offers a true differential input. It has a frequency response from 0.5 Hz to 1 MHz and three switched gain settings of x10, x100 and x1000. It is a general purpose preamplifier which has the facility to be connected to grounded sources in a manner which breaks ground loops and since it has a truly differential input it can be used to measure floating sources, such as the output from an AC bridge, without imposing an asymmetrical load onto the source.

Model 5188
Optical Input Preamplifier
The model 5188 preamplifier has an optically sensitive input and is designed to be used as a light to voltage converter in situations where the signal to be amplified is derived from an optical source. There are two versions of the product, differing only by the nature of the input detection device. The model 5188A has an InGaAs device which responds to near infra-red radiation while that in the model 5188B is silicon based and operates in the visible region of the electromagnetic spectrum.