Ideal Spectroscopy Photodiode Variable Bias Module, 0-24 VDC 24V, 2A DC Converter Power Supply Included This is an 0-24 VDC Ideal Spectroscopy photodiode variable bias module with included 24V, 2A DC power supply. This module is used to apply a DC bias to a compatible photodiode for greater sensitivity and linearity, and more rapid time response. The bias voltage is adjusted via a rotatable knob on the side of the bias module. The photodiode must be attached via the input female BNC connector. The output is monitored by connection to the output female BNC connector. Optionally, the 0-24 VDC bias voltage may be monitored via connection to the bias monitor female BNC connector for precise voltage control. Photodiodes are light detectors used in many spectroscopy applications. An unbiased photodiode acts as a photovoltaic device, which generates a single electron of current per excitation event. The photodiode output may be monitored either by measuring the current produced or by applying a resistance to the photodiode output and measuring the voltage build up as current is impeded. Photovoltaic operation is the simplest mode of action and has minimal dark current. Unfortunately it suffers from low amplification, nonlinear voltage response over large dynamic ranges, and slow response due to a short depetion width and large junction capacitance. Unbiased photodiodes are best for slow or very low light applications. Photodiodes may be reverse biased to change their response from photovoltaic to photoconductive. Under reverse biasing the depletion width increases, the junction capacitance decreases, and the response speeds up. The current response is amplified and becomes more linear over a larger dynamic range than in photovoltaic mode. The cost of these enhancements is increased dark noise and the propagation of electrical artifacts from the biasing power supply to the photodiode output signal. Using a clean power supply, such as Ideal Spectroscopy’s photodiode bias module, is critical for good response. Biasing photodiodes is best for applications where rapid time response or high linearity over a large range of light intensities is needed. Photodiode Variable Bias Module Specifications: Compatible Photodiodes: Anode-grounded, photoconductive Input Voltage: 24 VDC nominal, regulated, <100 mV ripple preferred Input Connection Type: Barrel Receptical, 5.5 mm OD, 2.1 mm ID Photodiode Bias Voltage: 0.8 - 23.4 VDC, variable Photodiode Bias Maximum Current: 3 A, <100 mA typical Photodiode Bias Load Regulation: ±2% typical Photodiode Bias Line Regulation: ±1% typical Photodiode Bias Ripple: <50 mV peak-peak at typical load Photodiode Bias Connection: BNC female, center positive Bias Monitor Voltage: 0.8 - 23.4 VDC, variable Bias Monitor Connection: BNC female Output Voltage: 0 - 5 V typical Output Connection: BNCfFemale Operating Temperatures: -40 to 85 °C Operating Humidity: <85% RH non-condensing 24V DC Power Supply Specifications: Input Voltage: 90 - 240 VAC Input Frequency: 47-63 Hz Output Voltage: 24.0±1.2 VDC Output Voltage Ripple: ±1% Rated Output Current: 2.5 A Input Connector: NEMA 1-15P Output Connector: Barrel, 5.5 mm OD, 2.1 mm ID Output Connector Polarity: Center positive Safety Approvals: UL60950-1, cUL60950-1 EMC Approvals: FCC

Ideal Spectroscopy Mounted Large-Area Silicon Photodiode, Anode GroundedThis is a mounted large-area silicon photodiode. It is best used for large visible or near infrared beams or spots in the range of 350-1100 nm. The photodiode is anode grounded and is equipped with a female BNC electrical connection for easy compatibility with existing lab systems. This mounted photodiode is compatible with Ideal Spectroscopy’s photodiode variable bias module which provides a bias of 0-24 VDC for a faster, more linear, amplified response. The anodized aluminum photodiode housing has several mounting features. The front face is equiped with an internal SM1 thread that can connect to a 1" diameter lens tube or other standard optical aparatus. The back of the photodiode housing has an external SM1 thread for installation into threaded optical mounts for 1" OD optics and devices. There is a also a smooth 1" OD section for mounting into kinematic mounts with a 1" ID smooth bore. A 8-32 threaded hole on the base of the mount allows for direct connection to standard optical posts. Specifications: Active surface area: 13 mm2, square Peak responsitivity wavelength: 970 nm Typical responsivity: 0.65 A W-1 Dark current: 0.35 nA typical, 6 nA max at 10 V reverse bias Rise time: 14 ns at 10 V reverse bias Maximum reverse bias: 30 V Operating temperature range: -40 to 100 °C