Impedance converter and condenser microphone
AssigneeKabushiki Kaisha Audio-Technica
InventorHiroshi AKINO
Life of this patent
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Abstract
In an impedance converter using an electron tube as an active element, output impedance can be made sufficiently low, and the number of circuit elements therefor is decreased and a circuit configuration therefor is made simple. Provided is an impedance converter having an electron tube cathode-follower connected. The impedance converter includes a bias diode that provides a bias voltage to a cathode of the electron tube, high resistance elements that provide a voltage of the bias diode to a grid of the electron tube, a load circuit connected to the electron tube, and a complementary emitter output circuit including two transistors, respective bases of which are connected to one end and the other end of the bias diode.
Claims10
An impedance converter using an electron tube as an active element, and having the electron tube cathode-follower connected, the impedance converter comprising:
- a bias diode that provides a bias voltage to a cathode of the electron tube;
- a high resistance element that provides a voltage of the bias diode to a grid of the electron tube;
- a load circuit connected to the electron tube;
- and
- a complementary emitter output circuit including two transistors, respective bases of which are connected to one end and an other end of the bias diode.
A condenser microphone that converts an audio signal at high impedance output from a condenser microphone module into an audio signal at low impedance and outputs the audio signal by an impedance converter,
- the impedance converter being an impedance converter using an electron tube as an active element, and having the electron tube cathode-follower connected,
- the impedance converter including:
- a bias diode that provides a bias voltage to a cathode of the electron tube;
- a high resistance element that provides a voltage of the bias diode to a grid of the electron tube;
- a load circuit connected to the electron tube;
- and
- a complementary emitter output circuit including two transistors, respective bases of which are connected to one end and the other end of the bias diode.
Dependencies are inferred from the claim text.