Sensar Mutane: Tsarin Haɗa, Turukan Da Kuma Zaburin Rikitar Da Kyakkyawanƙu
Mata shi a Voltage Sensor
Voltage sensor shine aiki a gaba da kuma kula da adadin voltage a kan abu. Voltage sensors zai iya tabbatar da masu AC ko DC. Input zuwa wannan sensor shine voltage, amma output yana iya kasance switches, analog voltage signal, current signal, ko audible signal.
Sensors suna cikin kayan aiki da suke magana da ko daga wani abu na electrical ko optical signals. Amfani da voltage sensor da current sensor techniques ta zama zabe ta hanyar amfani da hukumar daɗi na voltage da current.
A nan za a tafi sharhi game da voltage sensor. Voltage sensor yana iya tabbatar da kula da adadin supply of voltage. Yana iya kula da AC level ko DC voltage level. Input zuwa voltage sensor shine voltage, amma output yana iya kasance analog voltage signals, switches, audible signals, analog current levels, frequency, ko frequency-modulated outputs.
Haka, wasu voltage sensors suna iya bayar sine ko pulse trains as output, kuma wasu suna iya bayar amplitude modulation, pulse width modulation, ko frequency modulation outputs.
A voltage sensors, measurement an yi a matsayin voltage divider. Biyu na main types of voltage sensors ne: capacitive type voltage sensor da resistive type voltage sensor.
Capacitive Voltage Sensor
A sani a cikin capacitor ya ƙunshi biyu na conductors (ko biyu na plates); bayan hawa na plates, ana iya ƙara non-conductor.
Wannan non-conducting material ta amsa dielectric. Idan AC voltage an bayar across hawa na plates, current zai faru don attraction ko repulsion na electrons via opposite plate’s voltage.
Field among the plates zai ƙunshi complete AC circuit without any hardware connection. Haka ne yadda capacitor ya yi aiki.
Nan za a tafi sharhi game da voltage division in two capacitors which are in series. Duk da cewa a series circuits, high voltage zai faru across the component with high impedance. A case of capacitors, capacitance and impedance (capacitive reactance) suna da alaka inversely proportional.
The relation between voltage and capacitance is
Q → Charge (Coulomb)
C → Capacitance (Farad)
XC → Capacitive reactance (Ω)
f → Frequency (Hertz)
Daga hawa biyu na relations, muna iya cewa high voltage zai faru across the smallest capacitor. The capacitor voltage sensors sun yi aiki a cikin wannan principle. Za a yi lura a cikin sensor, then placing its tip near a live conductor.
A nan, muna iya ƙara sensing element da high impedance into a series capacitive coupling circuit.
Presently, the sensor’s tip is the smallest capacitor coupled to the live voltage. Thus, the whole voltage zai faru across the sensing circuit, which can detect voltage, and the light or buzzer indicator is turned on—this is behind the non-contact voltage sensors you use at home.
Resistive Voltage Sensor
Two ways exist to convert the resistance of the sensing element to the voltage. The first one is the simplest method, which is to provide a voltage to the resistor divider circuit comprised of a sensor and a reference resistor, which is represented below.
The voltage developed across the reference resistor or sensor is buffered and then given to the amplifier. The sensor’s output voltage can be expressed as
This circuit’s drawback is that the amplifier present will amplify the whole voltage developed across the sensor. However, it is better to amplify only the voltage change due to the change in the sensor’s resistance, which is achieved by the second method implementing the resistance bridge, as shown below.
Here, the output voltage is
When R1 = R, then the output voltage becomes approximately
A → Gain of instrumentation amplifier
δ → Change in the resistance of the sensor, which is analogous to some physical action
In this equation, the gain must be set high because only the voltage change due to the change in the sensor’s resistance is being amplified.
