| 摘要 |
PURPOSE: To obtain an output which is high in signal level by employing an amplifier element having 1st and 2nd input terminals and one output terminal, connecting a 1st ground circuit to the 2nd input terminal, connecting the 1st input terminal to ground in terms of high frequencies, connecting a 2nd ground circuit to the 1st input terminal and connecting the 2nd input terminal to ground in terms of high frequencies. CONSTITUTION: A capacitor 301 of a 1st ground circuit 3 is placed between a ground GND and a terminal 300 connected to a base, that is a 2nd input terminal of a transistor(TR). The impedance of the capacitor 301 varies with the frequency of a current I3 received from the terminal 300. Since the impedance of the capacitor 301 is smaller, when the frequency of the current I3 is high and the impedance of the capacitor 301 is higher, when the frequency of the current I3 is low, the terminal 300 of the 1st ground circuit 3 can be regarded as a ground point, in terms of high frequencies when the frequency of the current I3 is sufficiently high.
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