
Step 10 - Socket and 4049 hex inverter
The digital Logic NOT Gate is the most basic of all the logical gates and is sometimes referred to as an Inverting Buffer or simply a
Digital Inverter. It is a single input device which has an output level that is normally at logic level “1”and goes “LOW”to a logic level “0”
when its single input is at logic level “1”, in other words it “inverts”(complements) its input signal.
The output from a NOT gate only returns “HIGH”again when its input is at logic level “0― giving us the Boolean expression of: A
= Q.
In this circuit CMOS 4049 is main part it have 6 logic NOT gates and that means that input is inverted. Grounded input will give positive
output and that output is used to turn on LEDs and fed transistor base.
Latch circuit is created when two NOT gates are connected in series and one 2.2M resistor is connected in parallel with them. When
we put positive signal on input of first gate it will convert it to negative and second gate will convert that negative to positive, then that
positive signal is again transferred to first not gate via resistor and that is how we create latch circuit with not gates. Positive output is
used to feed transistor base. To break latch and turn off transistor we simply need to ground input of first NOT gate.
Main reason why socket is used is not to make easier component replacement but that chip is not damaged because of soldering and
to prevent changes in his operation caused by heat.
Firstly Insert the IC socket, noting the notch on the end. Make sure the notch of the socket lines up with the notch on the top silk image.
Use some tape to keep it in place, turn board and solder it. Check to make sure that the socket is seated flush on the board. If it’s not,
reheat your solders and push the socket it. Once it’s positioned correctly, solder all of the remaining pins.
Now when socket is properly soldered and cooled down you can place CMOS 4049. Place chip so that notch of chip is on the same
side like notch of the socket. Make sure that every leg of 4049 is in contact with socket connector.
Step 11 - Linear regulators 9V and 5V
In electronics, a linear regulator is a system used to maintain a steady voltage. The resistance of the regulator varies in accordance
with the load resulting in a constant output voltage. The regulating device is made to act like a variable resistor, continuously adjusting
a voltage divider network to maintain a constant output voltage, and continually dissipating the difference between the input and
regulated voltages as waste heat. By contrast, a switching regulator uses an active device that switches on and off to maintain an
average value of output. Because the regulated voltage of a linear regulator must always be lower than input voltage, efficiency is
limited and the input voltage must be high enough to always allow the active device to drop some voltage.
Linear regulators can be constructed using discrete components but are usually encountered in integrated circuit forms. The most
common linear regulators are three-terminal integrated circuits in the TO220 package.
Common solid-state series voltage regulators are the LM78xx (for positive voltages) and LM79xx (for negative voltages), and common
fixed voltages are 5 V (for transistor-transistor logic circuits) and 12 V (for communications circuits and peripheral devices such as disk
drives). In fixed voltage regulators the reference pin is tied to ground, whereas in variable regulators the reference pin is connected to
the center point of a fixed or variable voltage divider fed by the regulator's output. A variable voltage divider (such as a potentiometer)
allows the user to adjust the regulated voltage.
This circuit have two voltage regulators first one decreases 12V from input to 9V. 9v is used to supply IC 4049 diodes and latch circuit,
5V is used to supply relay module or other equipment, when water pump runs there is 5V signal on PCB headers.