In this study the authors have designed a multipurpose single channel bio signal amplifier for recording of ECG/EEG/EMG for clinical applications. To accomplish this we have used only three dry electrodes along with simple EEG leads to obtain the above Bio Potential signals. The authors have used the amplifiers INA 217 which has low noise and OP-07C. The results indicate that the signal extracted is very much free from noise. Furthermore the performance analysis of this pre amplifiers has been carried out and shows low Noise of 1.69nV/. Also the outcome gives the SNR approximately 57.79 dB with a very high input impedance of 711.11Kω and low output impedance 150ω. © 2015 IEEE.