DETECTOR CIRCUIT

• Main Authors: IKEDA I,JA, HONGU M,JA
• Format: Patent
• Language: English
• Published: 03.12.1974
• Subjects: BASIC ELECTRONIC CIRCUITRY; DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TOANOTHER; ELECTRICITY

The detector circuit is divided into two parts, a signal current input section and a detector section. The signal current input section includes an input terminal which is supplied with a signal to be detected and which is connected to the base electrode of a first transistor whose collector electrode is connected through a first impedance to a first terminal of a voltage source and whose emitter electrode is connected through a second impedance to a second terminal of a voltage source. The detector section includes a second transistor whose collector electrode is connected through a load impedance to the first terminal of the voltage source and whose emitter electrode is connected through a diode to a second terminal of the voltage source, the diode being connected such that its conductive polarity is the same as the conductive polarity of the junction between the base and emitter electrodes of the second transistor with respect to the voltage source. Means are provided for connecting the emitter electrode of the second transistor to the collector electrode of the first transistor and the base electrode of the second transistor is based so that a small current flows through the second transistor and the diode when no input signal current is supplied. The output from the detector circuit is delivered at the collector electrode of the second transistor so that the detector circuit operates with great linearity over a wide range of input signal values.