Cooknell Electronics Ltd, Dorset - Picoammeter CP13

The CP13 is a combined DC ammeter and current source for use over the current range 12x10^-14A FSD to 12x10^-3A FSD in 23 ranges. As standard, the instrument is battery operated for portable operation. A mains powered version is also available. The CP13 can be used with the Cooknell 1010 EHT Supply for measurement of insulation resistance / leakage current at test voltages up to 1000V.

As an ammeter, the CP13 maintains it's virtual earth within 50µV of earth for signals from zero to FSD and has an equivalent input drift typically less than 200µV over a period of 10 hours after an initial 1 hour settling period.

As a current generator, it has an equivalent source voltage of greater than 1kV and will tolerate a load voltage deviation from earth of more than 1.5V. A 'VE Potential' socket on the rear panel provides a buffered output of the voltage across the load. With the current output connected to a known capacitance, the CP13 operates as a linear voltage ramp generator. An adaptor is available for this purpose (CP13-R1). The ramp output is taken from the VE Potential socket.

The CP13, is manufactured as either an analogue or digital version and also free-standing or rack mounted. The analogue version has sockets on the rear panel for connection of a digital volt meter for more accurate measurements.

Specifications:

All specifications at 20°C unless otherwise stated and after ten minutes settling period. As the same measuring components are used for current generation and current measurement, the specifications for the two modes are identical. Meter tolerances given are for the analogue version.

Range	Meter Error	O/P Error	Temp. Co.	Typ. Stability
(A FSD)	(%)	(%)	(ppm/°C)	(% Per Year)
12x10^-3 & 4x10^-3	1.0	0.3	±50	±0.1
12x10^-4 to 4x10^-8	1.0	0.2	±50	±0.1
12x10^-9 to 4x10^-10	2.0	1.0	±100	±0.1
12x10^-11 to 4x10^-11	2.0 *	1.0 *	±150	±0.1
12x10^-12 to 12x10^-14	3.0 *	2.0 *	-1200 typ	±0.5

* Plus residual current of 1x10^-14A max (2x10^-15A typ).

Input Offset With Temp.	±100uV/°C max
Input Offset With Signal	50uV max (zero to FSD)
Input Offset With Time	±50uV/h typ
Current Generator	Apparent voltage >1kV
	Load voltage ±1.5V max
Input Overload Withstand	50V dc or rms ac on 4x10^-3A and 12x10^-3A ranges
	250V dc or rms ac on all other ranges
Input Capacitance	2nF max in measure mode, unlimited in generate mode
Dimensions	430 x 146 x 254mm deep (free standing version)
Weight	5.2kg free standing, 6kg rack mounted

This instrument is also available 3U rack mounting.

Available Accessories:

CP13-T1	Transistor Adaptor for TO-18 EBC
CP13-T2	Transistor Adaptor for TO-18 BEC
CP13-T3	Transistor Adaptor for TO-5 EBC
CP13-T4	Transistor Adaptor for TO-5 dual
CP13-R1	Ramp Generator Adaptor