- Civil Lab Mechanical Lab Engineering Lab Equipments | sales@didacticlabequipments.com

CAT NO: DIDACTICELECTROMETER0101

DIELECTRIC CONSTANT OF A CAPACITOR.

DIELECTRIC CONSTANT OF A CAPACITOR The relationship between capacitance C, charge Q and voltage
V is described by ratio C=Q/V.
The capacitance of a parallel plate capacitor depends on
distance “d” between its plates, on area A of plates and on the
insulating material between the plates and especially on its
dielectric constant.
The first test concerns the measurement of charge Q of the
capacitor versus voltage V. Consequently, capacitance is
determined as slope of Q-vs-V curve.
The measurement will be carried out at a fixed distance “d”
with different areas of plates, in the second test. Distance can
be varied by steps of 1 mm.
The variation of distance “d” between plates of constant area A
will confirm proportionality Cαa1/d, in the third test.
The permittivities of two different dielectrics (polystyrene and
glass) between the capacitor plates will be determined in the
fourth test.
TRAINING PROGRAM
• determining the capacitace of a plate capacitor by
measuring its charge
• measuring capacitance versus the area of plates
• measuring capacitance versus the distance between plates
• determining the dielectric constant of different materials
COMPONENTS
• kit of dielectric constant
• electrometer amplifier
• digital multimeter
• flexible cables
KIT OF DIELECTRIC CONSTANT
It includes a rail with a scale of 0-10 cm printed on a side, 2
wide plates and 2 small plates for capacitor, spacers of PVC,
pane of glass and plate of polystyrene, capacitive module.
DISASSEMBLABLE CAPACITOR
Area of (aluminium) plates : 400 mm2, 800 mm2
Intervals : variable, 1, 2, 3, 4, 6 mm
Pane of glass: 21 x 21 cm
Plate of polystyrene : 21 x 21 cm
ELECROMETER AMPLIFIER
Electrometer ampplifier used to measure the charge
Input impedance > 1013 Ω
Input current ≤0.5 pA
Output voltage: up to +10 V
Output current: 5 mA
Output impedance = 1 Ω
Supply voltage: 12 Vac
DIGITAL MULTIMETER
Resistance range: 200 Ω, 2000 Ω, 20 k Ω, 200 k and 2000 k Ω
DC voltage: 200 and 2000 mV
20, 200 and 1000 V
AC voltage: 200 and 750 V
Direct Current: 200, 2000 μA
20 and 200 mA
10 A