L7800 SERIES
Figure 30 : Power AM Modulator (unity voltage gain, IO ≤ 0.5)
NOTE: The circuit performs well up to 100 KHz.
Figure 31 : Adjustable Output Voltage with Temperature Compensation
VO = VXX (1+ RR21 ) + VBE
NOTE: Q2 is connected as a diode in order to compensate the variation of the Q1 VBE with the temperature. C allows a slow rise time of the VO.
Figure 32 : Light Controllers (VOmin = VXX + VBE)
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VO falls when the light goes up
VO rises when the light goes up