| 摘要 |
PURPOSE:To eliminate the drift of voltage gain due to temperature changes by securing a positive change to the temperature for the inter-terminal voltage of the load resistances of cascaded transistors TR. CONSTITUTION:The input video signals, etc. are supplied to the base of a TRQ1 via a capacitor 1 and then amplified by TRs Q1 and Q2 to appear at the collector of the TRQ2. These amplified signals are extracted via an emitter follower of a TRQ3. While the base voltage of the TRQ3 is equal to the base voltage of a TRQ4, i.e., the reference voltage Vr since TRs Q1-Q3 are fed back in terms of DC via an error amplifier 5 and an integration circuit. At the same time, diodes D1-Dn have the characteristics a forward voltage frop VF having a negative temperature coefficient of about 1.7mV/degree. Therefore the inter- terminal voltage of a load resistance RL increases in response to the rise of the ambient temperature. The rise of this inter-terminal voltage is regarded as an increase of the collector current ICQ2 ICQ1 of cascaded TRQ1 and Q2. Thus the circuit gain is compensated to the drift of temperatures.
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