Block Diagram Voltage Regulator. The unregulated ac voltage is connected to a transformer which steps that ac voltage down to the level for the desired dc output. The functional blocks of the regulator illustrated in figure 6 are.
As shown the input is applied to the pass element. The resulting desired output voltage is sensed by error amplifier. The automatic voltage regulator is used to regulate the voltage.
The 7900 series are negative voltage regulators.
The output voltage is then fedback to a sampling circuit and then compared with a reference voltage and sent back to the output. Lm78xx circuit diagram description. As shown the input is applied to the pass element. The resulting desired output voltage is sensed by error amplifier.