IC 7805
Fixed voltage Positive and Negative regulator ICs are used in circuits to give precise regulated
voltage.78 XX series regulator IC can handle maximum 1 ampere current. The Regulator ICs require minimum 1.5 higher input voltage than their voltage rating. For example 7805 IC requires minimum 6.5 volts to give 5 volt output. Here are some circuit designs of IC 7805 to monitor the output voltage.
This is the manipulation of the Regulator IC 7805 to give 9 volt regulated output. Normally the pin2 of the regulator IC is connected to the ground. Here it is connected to a 3.9 volt Zener diode. So the output from the Regulator IC will be 9 volts.
Regulator IC 7805
This circuit can tell whether the IC 7805 is giving output or not. IC 7805 requires minimum 6.5 volt input to give 5 volt regulated output. When the input voltage is above 6.5 volts, Zener conducts and LED turns on indicating sufficient input voltage. Diffuse type Red
LED requires 1.8 volts and Zener 4.7 volts .So to activate both these, input voltage should be minimum 6.5 volts. If the input voltage drops below 6.5 volts, Zener cutoff and LED turns off. This indicates the zero output from the regulator IC.