Broadband AC isolation amplifier with frequency band 600kHz

This is a simple isolation amplifier composed of a high-speed optocoupler and a transistor circuit
. It cannot carry out DC (direct current) transmission. It is suitable for DC signal
isolation. It has good frequency characteristics and the frequency is 600 kHz:_3dBo
    ·Circuit operation Principle:
    In order to make the optocoupler work under no modulation conditions, a DC value must be applied
. The function of the transistor Tfl is to provide a DC bias current for the LED. A silicon diode is connected between the base and ground
to improve the temperature characteristics.
    Use of rate circuit The optocoupler is 6N136. The output current of the photodiode
is relatively small, so a body tube is used to amplify the current. In order to improve the frequency characteristics
, the base ground circuit composed of Tr earth converts the electricity/to the voltage
    of the port circuit. The voltage gain is determined by the electrode resistance of Tra. In order to make
^ = odB, a 1.8kQ resistor is used. The adjustment of the operating point is completed by the transmitting and receiving
resistor . When determining the bias, the linearity of the maximum input signal should be ensured. Best
(low distortion rate).