Amplifier Circuit Gain Control Without a Transformer
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Solution Overview
Problem
Conventional amplifier circuits that use transformers for automatic gain control are costly, and without transformers, they struggle to supply a sufficient detection signal level and stable bias voltage to transistors.
Innovation Solution
The amplifier circuit design includes a first pathway between the collector and base of the first transistor to supply the detection signal to the second transistor and a second pathway between the emitter and base of the first transistor to supply a stable bias voltage, eliminating the need for a transformer and enabling effective automatic gain control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transformer is used in the amplifier circuit to supply detection signal and bias voltage, then the detection signal level and bias voltage stability are sufficient, but the cost increases
Solution Approach 1:
The patent divides the single transformer function into two separate pathways: one pathway (collector to base) supplies the detection signal, while the other pathway (emitter to base) supplies the bias voltage. This segmentation eliminates the need for a transformer while maintaining both functions independently and effectively.
2Ease of manufacture
If the amplifier circuit is configured without using the transformer to reduce cost, then the cost is contained, but the detection signal level from the emitter decreases making it impossible to supply the detection signal
Solution Approach 1:
The patent separates the detection signal path from the bias voltage path by using two distinct pathways. The first pathway connects the collector to the base to supply the detection signal with sufficient level, while the second pathway connects the emitter to the base to supply the bias voltage. This segmentation allows the circuit to function without a transformer.
3Ease of manufacture
If the amplifier circuit is configured without using the transformer to reduce cost, then the cost is contained, but it becomes impossible to supply both detection signal and stable bias voltage simultaneously
Solution Approach 1:
The patent creates two independent pathways that branch from different points of the first transistor: the collector pathway for detection signals and the emitter pathway for bias voltage. This segmentation enables the circuit to simultaneously provide both functions without requiring a transformer, maintaining cost-effectiveness while preserving full functionality.
Data Source
AI summary
An amplifier circuit includes a first transistor, a second transistor, a first pathway and a second pathway. The first transistor amplifies an external signal that is input from outside the amplifier circuit. The second transistor amplifies a detection signal that detects a level of the external signal. The first pathway is connected between a collector of the first transistor and a base of the second transistor to supply the detection signal that is output from the collector of the first transistor to the base of the second transistor. The second pathway is connected between an emitter of the first transistor and the base of the second transistor to supply a bias voltage from the emitter of the first transistor to the base of the second transistor.