IC 741 is the most used and popular operational amplifier IC, because of its unique feature and low price. Various op-amp 741-based projects are already posted in the operational amplifier-based projects section. Now, here is a simple project using a couple of op-amps 741 IC called voltage into frequency converter.
Description of voltage into frequency converter Circuit using 741 IC
The circuit of voltage into frequency converter consists of a couple of op-amp 741, a couple of transistors, and a few passive components (resistors). The voltage of 0.5V to 15V is given to Vin pin 2 of IC1 through VR1 and resistor R1 and is converted to its corresponding frequency. This circuit posted here can also be used as voltage measurement in digital form.
IC1 is configured in inverter mode and IC2 in Schmit trigger mode. The output of IC1 is dependent on input voltage and is given to the input of IC2. IC2 becomes ON and OFF in fixed time intervals. The triangle wave is obtained at the output of IC2. A Triangle wave is further amplified and changed into a square wave by two transistors T1 and T2. This square wave is given to counter roe reading.
PARTS LIST OF VOLTAGE TO FREQUENCY CONVERTER CIRCUIT USING 741 IC
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Resistor (all ¼-watt, ± 5% Carbon) |
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R1 = 1 MΩ R2 = 18 KΩ R3 = 10 KΩ R4 = 220 KΩ R5 = 100 KΩ R6 = 2.2 KΩ R7 = 2.7 KΩ R8 = 10 KΩ R9 = 12 KΩ VR1 = 500 KΩ VR2 = 5 KΩ |
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 Capacitor |
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 C1 = 0.1 µF (Ceramic Disc) |
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Semiconductors |
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IC1, IC2 = 741 (General Purpose Operational Amplifier) D1 = 1N34 (Germanium Diode) T1, T2 = BC108 (general purpose low power Silicon NPN bipolar junction transistors ) |
TELL ME THE CAPACITANCE OF C1 CAPACITOR
Thank you for recalling, I have updated the value of capacitor c1
please tell me where exactly the input is given either 2nd or 3rd terminal of first IC and tell me about the 4th terminal in second IC
Pin 2 2 and 3 of IC1 is connected as shown in circuit diagram and pin 4 of IC2 is zero potential pin which is not necessary to connect.
Can i use fixed resistor instead of variable resistors used above
You most have to use variable resistor.
hello
what is vin? pulse or dc
Its DC voltage
i want to know how to check frequency at output
You may check using pspice.
sir can i know complete project details of under and over voltage indicator with op amp window comparator
i think the square wave should be obtained at the output of 2nd IC itself as it is in Schmitt Trigger mode, the transistors ahead just amplify it.
my simulation of the above circuit is not coming correct in multisim
what is the formula to calculate frequency theoreticaly
sir,telll us the use of frequency converter and its advantage
why we need frequency converter.
what will be output of voltage into frequency converter by lm 741 ic?
How to calculate the theatrical frequency?
How to get the output for voltage to frequency converter?
is it easy to design the ciruit
i am 2nd year student our group has joined to do a small project.please recommend some of the small and simple projects
how to measure the output frequency?
will u please upload video of above expt
plz upload video
Sir, where should I get the output and what is the formula for frequency. I did transient analysis but it was dc