Owens Bridge Circuit da Abubuwan ƙaɗan
A kan da cikin sune bridges masu yawan inda za a iya kawo indukta kuma ya zama quality factor, kamar Hay’s bridge wanda yake da kyau don kawo quality factor da yake da fili 10, Maxwell’s bridge wanda yake da kyau don kawo quality factor na tsawon 1 zuwa 10, kuma Anderson bridge zai iya amfani da shi don kawo indukta daga micro Henry zuwa Henry. Saboda haka, wani abubuwan da muke so ku fada Owen’s Bridge?.
Amsa a wannan tambayar tana da kyau. Muna buƙata bridge wanda zai iya kawo indukta a cikin tsawo mai yawa. A cikin bridge circuit da zai iya yi haka shine Owen’s bridge.
Wannan shine AC bridge kamar Hay’s bridge da Maxwell bridge wadanda suke amfani da standard capacitor, induktors da variable resistors da suke kula da AC sources don excitation. Ba ni gane in bincike Owen’s bridge circuit a cikin bayanai.
Theory of Owen’s Bridge
An Owen’s bridge circuit ta haɗe.
AC supply ta kula a matsayin a da cikin a da c. Arm ab ta da indukta da take da resistance mai fili, ba ni gane a markar da r1 da l1. Arm bc ta da electrical resistance mai fili a markar da r3 kamar yadda ake nuna a cikin figure da aka bayyana, kuma ya zama current i1 a balance point wanda yake daidai da current da arm ab ta da.
Arm cd ta da pure capacitor da ba ta da electrical resistance. Arm ad ta da variable resistance da variable capacitor, kuma detector ta kula a matsayin b da d. Yanzu, yana da yin haka? Wannan bridge ta kawo indukta a cikin capacitance. Ba ni gane in samun expression don indukta don wannan bridge.
Haka l1 shine unknown inductance kuma c2 shine variable standard capacitor.
A balance point, akwai relation daga AC bridge theory wanda yake da kyau i.e.
Putting the value of z1, z2, z3 and in above equation we get,
Equating and then separating the real and the imaginary parts we get the expression for l1 and r1 as written below:
Now, there is a need to modify the circuit, in order to calculate the incremental value of inductance. Given below is the modified circuit of Owen’s bridge:
A valve voltmeter is placed across the resistor r3. The circuit is fed from both AC and DC source in parallel. The inductor is used to protect DC source from very high alternating current and the capacitor is used to block direct current from entering the AC source. The ammeter is connected in series with battery to measure the DC component of current while the AC component can be measured from the reading of the voltmeter (which is not sensitive to DC) connected across the resistance r3.
Now at the balance point we have, incremental inductor l1 = r2r3c4
also inductor
Therefore incremental permeability is
N is the number of turns, A is the area of flux path, l is the length of flux path, l1 is incremental inductance.
Let us mark drop across arm ab, bc, cd and ad as e1, e3, e4 and e2 respectively as shown in the above figure. This will help us to understand the phasor diagram well.
In general the most lagging current (i.e. i1) is chosen as reference in order to draw phasor diagram. Current i2 is perpendicular to current i1 as shown and drop across inductor l1 is perpendicular to i1 as it is an inductive drop while the drop across capacitor c2 is perpendicular to i2. At balance point e1 = e2 which is shown in the figure, now resultant of all these voltage drops e1, e2, e3, e4 will give e.
Advantages of Owen’s Bridge
The for inductor l1 that we have derived above is quite simple and is independent of frequency component.
This bridge is useful for the measurement of inductor over wide range.
