Voltage to Frequency Converter Using LM331
Category: Miscellaneous
Designer: RANA MUHAMMAD ADNAN KHALIL
Notes
This circuit is designed and simulated in Proteus 7.10. This is a very useful circuit for converting voltage into frequency. 1. LM331 IC is used for converting voltage into frequency. 2. The input voltage range is from 0 to 10VDC via potentiometer RV3. 3. The output frequency range is from 10Hz to 10kHz. 4. The resistor R1 and C3 are used to filter input voltage. 5. The potentiometer RV1 is used for adjustment of conversion factor. 6. The potentiometer RV2 is used for fine tuning of conversion factor. 7. The conversion factor is set 1kHz for 1V and it is linear, that is 100Hz for 0.1V and 10Hz for 0.01V. 8. Initially the 3V is applied at Vin, and the output frequency is 3kHz, when the Vin is 5V the frequency out is 5kHz and when Vin is 6.7V the Fout is 6.7kHz. 9. The conversion ratio is Fout = (Vin/2.09V) x (Rs/RL) x (1/RtCt) 10. The conversion is almost linear throughout the range. Applications: 1. This circuit be used as a feedback for analog voltage. 2. This circuit is used as voltage to frequency converter with your customized conversion ratio. 3. This circuit can be used as remote sensor monitoring. Note: More useful circuits are coming soon, stay tuned.