The 4114B1 model manufactured by Dytran Instruments Inc. is a line-operated constant current power unit made to power IEPE sensors and in-line charge amplifiers. This product gives 2 to 20 mA of constant current at +24 VDC compliance voltage. It is a 4-channel unit equipped with four BNC sensor jacks and four BNC output jacks. The rear panel of the unit is mounted with electrical connectors. The Dytran model 4114B1 have an integrated and highly regulated +24 VDC power supply with adjustable constant current circuits. The constant current circuits are made of clamped-base PNP transistors with variable emitter resistor to adjust the current. Users can change the current output of the circuits with the limits set from 2 to 20mA. The rear-panel sensor jacks supplies to the sensors its constant current. This product is available in a stand-alone desktop unit or it can be rack mounted in an 19-inch wide by 5.25-inch high rack adaptor.