Spanning transformator AC sensor 2mA 1-1 2mA analoog ZMPT101B

Beschrijving

ZMPT101B is a high-precision voltage Transformer. This module makes it easy to monitor AC mains voltage up to 1000 volts. A tiny little thing the size of a bouillon cube. Holds up to 4kV per breakdown voltage, the ratio of turns is 1: 1, but this is a current transformer of 2mA: 2mA. We feed it a current and remove the current. The input current is simply set by the resistor in series R1, and we use a sampling resistor R2 in parallel to get the output voltage.

Features:

• High galvanic isolation

• Wide Range

• High accuracy

• Good Consistency

Specification:
Product model: ZMPT101B

Rated input current: 2mA

Rated output current: 2mA

Change ratio: 1000:1000

Phase difference: ≤20′

Linear range: 0~1000V 0~10mA

Linearity: ≤0.2%

Allowable error: -0.3≤f≤0.2%

Isolation withstand voltage: 4000V

Uses: accurate measurement of voltage and power

Sealing material: epoxy resin

Installation method: printed board installation

Working temperature:-40 to +60 degrees

Shell material: ABS

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ZMPT 101B Transformer Calculation

R1 is chosen so that the current through the winding does not exceed 2mA, it holds a maximum of 10mA, but after 2mA linearity is lost and the output will be clear that.

Step 1: Determination of maximum output RMS voltage

VOutmax is decided by the ADC peak voltage in the sampling loop of Microcontroller.
For Bipolar ADC

VOutmax=(Peak Voltage)/(√2)

For example
As for ± 5V ADC, the maximum RMS voltage of the transformer:

VOutmax=(Peak Voltage)/(√2)=5V/(√2)=3.53V

For Unipolar ADC

VOutmax=(Peak Voltage)/(2√2)

For example
As for 0-3.3V ADC, the maximum RMS voltage of the transformer:

VOutmax=(Peak Voltage)/(2√2)=3.3V/(2√2)=1.16V

Step 2: Determination of input current-limiting resistor R1

Current-limiting resistor

R1=Vin/I

Where
Vin : Rated input voltage
I ： Rated operating current （ when Coil resistance is compared with current-limiting resistor R1, it can be ignored.）

ZMPT101B usually working at rated current: 1~2mA.
When Rated input voltage ≤ 100V ，Usually choosing the operating current I=2mA; When Rated input voltage ≥ 220V，To reducing the resistor power， usually choosing the operating current 1 mA ≤ I ≤ 2 mA.
for example V=100V，I=2 mA，

R1=Vin/I=100/0.002=50kΩ

for example: V=220V，I=1.1 mA，

R1=Vin/I=220/0.0011=200kΩ

To improve reliability, the current-limiting resistor selected usually is greater than its 4 times the rated power, and generally, uses a high temperature coefficient metal film resistor.

Step 3: Determination of the sampling resistor R2

R2=VOutmax/I=(VOutmax/Vin)×R1 Ω

for example: Voutmax =3.53V，Vin =100V

R2=VOutmax/I=(VOutmax/Vin)×R1=(3.53/100)×50 kΩ=1.765kΩ

The above formula is also suitable for the two ways of active and passive output.
When selecting the sampling resistor, Resistor should not exceed

R2=VOutmax/I=VOutmax/Vin×R1 Ω