Note that the Current & Voltage Probe System (NO LONGER AVAILABLE) (CV-BTA, discontinued) is no longer available, and has been replaced by the combination of:
Current Probe (DCP-BTA) and
Differential Voltage Probe (DVP-BTA)
The Dual Channel Amplifier (the box part of the CV system) consists of two independent differential amplifiers. Each amplifier has two input leads, a + lead and a – lead. In order to have to reading default to zero when no sensor is attached, we have a resistor on each + and – input (specified below). In order to have the reading be zero when only one lead is attached, we have a resistor between the + and – input.
Resistance to ground (+ input or – input)
CV-DIN = 1M ohm (model used with ULI and SBI)
CV-BTA = 10M ohm (model used with CBL,CBL2, and LabPro)
Resistance between leads (+ input to – input)
CV-DIN = 10K ohm (model used with ULI and SBI)
CV-BTA = 1M ohm (model used with CBL,CBL2, and LabPro)
These resistors result in a relatively low input impedance. Because the system is primarily used on “bulb and battery” type of circuits, this is usually not a problem. If the low input impedance is a problem, the easiest solution is to use a smaller resistor in whatever circuit that is being monitored. If this is not an option, contact our Tech Support dept to discuss other options.