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Posts Tagged ‘TL082’

1kH Synthetic Inductor using TL082

Inductors can be mimicked quite easily using operational amplifiers. The circuit shown here was developed to have an inductance of 1000 H (say, one thousand Henry) with good damping. Using this design you can build a resonant circuit with a center frequency of less than 1 Hz. The slow behavior allows you to use conventional measuring instruments to investigate the circuit in real time. The circuit can also be used as part of a ?lter design. Opamp1 operates as an Integrator, Opamp2 as a difference amplifier.
The output voltage of Opamp2 is equal to the voltage drop across R1 and P1, which is proportional to the output current. This voltage is differentiated by Opamp1, C1 and R2. The net effect is that the circuit behaves as an inductor. P1 allows adjustment of the inductance value. P2 allows adjustment of the Q factor of the coil by altering the symmetry of the difference amplifier and with it the stability of the circuit.
link: http://www.extremecircuits.net/2010/08/1kh-synthetic-inductor.html

Be the first to comment - What do you think? Posted by admin - May 26, 2011 at 2:46 am

Categories: Basic electronics, Op-amp circuit Tags: induction coil, synthetic inductor circuit, TL082

0-1V to 4-20 mA Converter by TL082

Ensure +5/-5 dual supply for chip TL062 IC3. Gnd is common ps ground, let grounds radiate from ground plane in one side of PCB. R3-R8 is an attenuator that may need to be designed or modified.
In output R23 is for protection from shorting of +5V supply, R23 can also go to an unregulated or external
supply upto 24V DC which is referenced to this circuits gnd. More voltage more distance.

Q2 is the current control device, and R22 50E is the shunt for taking a sample of current. 4-20mA in the output (provided suitable load is connected) means 200mV- 1000mV across 50E shunt. This is fed to close loop control system of IC3a inverting pin.
An opamp on this type of feedback tries to drive the output in such a way, so as to maintain both the inputs at same level.
Source:http://schematics.blogspot.com/2005/10/0-1v-to-4-20-ma-converter.html

Be the first to comment - What do you think? Posted by admin - March 14, 2008 at 11:39 am

Categories: Converter Circuit, Op-amp circuit Tags: signal converter circuit, TL082, voltage to current converter circuit

Sawtooth wave oscillator By TL082

In this page, I introduce the sawtooth wave oscillator which used the operational amplifier (TL082).
The composition of this circuit is the same as the triangular wave oscillator basically and is using two operational amplifiers. At the circuit diagram above, IC(1/2) is the Schmitt circuit and IC(2/2) is the integration circuit.
The difference with the triangular wave oscillator is to be changing the time of the charging and the discharging of the capacitor. When the output of IC(1/2) is positive voltage, it charges rapidly by the small resistance(R1) value.(When the integration output voltage falls) When the output of IC(1/2) is negative voltage, it is made to charge gradually at the big resistance(R2) value. The output waveform of the integration circuit becomes a form like the tooth of the saw.
Such voltage is used for the control of the electron beam (the scanning line) of the television, too.
When picturing a picture at the cathode-ray tube, an electron beam is moved comparative slow.(When the electron beam moves from the left to the right on the screen)
When turning back, it is rapidly moved.(When moving from the right to the left)

Like the triangular wave oscillator, the line voltage needs both of the positive power supply and the negative power supply. Also, to work in the oscillation, the condition of R3>R4 is necessary. However, when making the value of R4 small compared with R3, the output voltage becomes small. The near value is good for R3 and R4. You may make opposite if not oscillating using the resistor with the same value. The circuit diagram above is using the resistor with the value which is different to make oscillate surely.

Read More Source link http://www.interq.or.jp/japan/se-inoue/e_ckt17.htm
Thank you