Circuit Project Design Archives - ETTRONICS

Difference Between Analog and Digital Electronics with Practical Examples

ettronics — Fri, 20 Mar 2026 05:59:41 +0000

Generally, every electronic circuit is either an analog circuit or a digital circuit. Analog circuits are often referred to as “Linear” circuits, we shall get to know why as we proceed. In this tutorial, you will learn: The components you need for this tutorial include: You may have seen the speedometer on a car dash board or the speed level graphics on your car race computer game. They are analog systems. In the car, as you apply pressure on the throttle or accelerator, the speed of the car increases with time and you can view the rate of this increase on your speedometer. Also, in your computer game, as you press the throttle button more, the speed level increases as well. In the two systems, if you reduce the pressure on the throttles, the speed levels go down. Such a system that varies with time is called an analog system. Analog vs digital Electronic Circuit In analog electronic systems, voltage or current is used to represent various physical measurements; like the speed of the car, temperature, humidity, pressure, amount of light, etc. When we want to electronically measure all these physical quantities that vary with time, we do so using an electronic system. An electronic system will convert these varying physical quantities, to varying voltages or currents that are proportional to the physical quantities being measured. This can be achieved by using analog electronic circuits that contain transducers. Transducers can be sensors, devices or systems that can convert one form of energy to another or one form of system to another. Figure 1 above shows a block diagram of a physical change measurement being converted to voltage or current using an analog electronic circuit. Figure 2 shows an electronic circuit that can convert a varying physical measurement to varying current. The circuit contains a light dependent resistor (LDR). A light dependent resistor is a resistor whose resistance varies with respect to the amount of light shining on it. As the light intensity on the LDR increases, its resistance decreases, and as the light intensity decreases its resistance increases. This constitutes a varying physical system. With the help of an analog electronic circuit, we can measure this varying light intensity in the form of current that flows through a light emitting diode (LED). When you turn on the switch, and gradually cover the LDR, the light intensity on the LDR decreases. The resistance of the LDR increases up to 10,000,000Ω = 10MΩ, when this happens, current flow through the LED will gradually reduce in intensity, because the resistance along its path of flow has drastically reduced as a result of the increased resistance of the LDR. But, when you gradually remove your hand from the LDR and have the LDR exposed in such a way that a reasonable amount of light shines on it, the resistance of the LDR will decrease tending to 0Ω. When this happens, the current flow through the LED will see little to no resistance on the LDR, the fixed resistance it will see is the 220Ω resistance of the current limiting resistor, which is there to protect the LED from getting fried from high current. So, as your hand is gradually removed from the LDR, the LED gradually brightens up. If this action of covering and uncovering of the LDR is gradually repeated, the LED will be gradually going ON and OFF. With this analog electronic circuit, we are actually monitoring and tracking light intensity. If we connect an ammeter in series with the LDR, we can measure the intensity of light on the LDR by multiplying the measured current by a factor. To learn how to use a multimeter like a professional, check out our Practical electronics circuit design course for the absolute beginner If we connect a voltmeter across the LDR, we can measure the voltage drop on the LDR. By multiplying this voltage value by a factor, we can measure the varying intensity of light on the LDR. The bottom line is this: we are tracking a varying physical system (change in light intensity) with varying voltage and current. This electronic circuit that takes in a varying input and in turn produces a varying output is called an analog electronic circuit. But if the system takes in a varying input and produces a steady output, like ON or OFF without a lower value ON (like a LED dimming as in the case above), such an electronic circuit is called a digital electronic circuit. Figure 3 above is a simple LED circuit to explain a digital system. When the switch is pressed, the LED comes ON with a steady brightness and when the switch is turned OFF, the LED goes off. In the event of pressing the switch, the LED is either ON or OFF, there is nothing like lower brightness or higher brightness. The LED having only an OFF or ON state is a typical digital electronic circuit implementation. In digital electronics, no matter the variation of the measured system, the output or result is either 0 or 1, HIGH or LOW, ON or OFF, 5 volts or 0 volts, 3.3 volts or 0 volts. Figure 3 above is similar to figure 2; the only difference is the removal of the LDR from figure 3. In the analog system, the varying brightness of the LED tells us that the system is analog, while in the digital system, the LED only takes two distinct stats, either ON or OFF. Some Components Used to Design Analog Circuits The design of analog electronic circuit requires bunch of discrete components and some integrated circuits (IC) listed below: We discussed most of these components in detail in our practical electronics circuit design course, a course that was created to take you from knowing nothing about electronics circuit design, to mastering the fundamentals of electronics circuit design from scratch. On the other hand, digital electronic circuits are built from logic gate integrated circuits. It’s quite disappointing that some

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Automatic Water Level Controller Project

ettronics — Fri, 12 Apr 2024 16:28:06 +0000

In this detailed tutorial, we’ll explore the process of making a water level controller without the need for a microcontroller. This project serves as an excellent opportunity to deepen your understanding of electronic components and their behaviours in circuits, paving the way for designing complex circuits without relying on microcontrollers like Arduino, PIC, or ESP32. To successfully design such a circuit, it’s crucial to master the behaviours of various electronic components. These components include resistors, capacitors, transistors, relays, thyristors, sensors, transformer, bridge rectifiers, voltage regulators, etc. each playing a vital role in the circuit’s functionality. Understanding how these components interact is key to designing an effective water level controller. For instance, sensors detect the water level and send signals to the circuit. Transistors act as switches, controlling current flow based on sensor input. Resistors and capacitors manage voltage and current flow for stability. Relays switch high-power loads like pumps, thyristors handle power control, transformer and bridge rectifiers convert AC to DC, and voltage regulators maintain a stable output DC voltage. By delving into the intricacies of these components and their roles in circuit design, you’ll not only create a functional water level controller but also gain valuable insights for future projects. This journey of discovery will empower you to design innovative electronic circuits without relying on microcontrollers. List of Materials for the Circuit Design S/N Component Description Quantity 1 Resistor 100R 4 2 Transistor TIP41 3 3 Thyristor BT151 1 4 Transformer 220V to 12V 1 5 Bridge rectifier KBP206 1 6 Capacitor 1000uF, 1uF 2 7 Voltage regulator 7805 1 8 Diode 1N4001 1 9 Relay 5V SPDT 1 10 Jumper wires Male to male Bunch Table 1.0 List of Materials for the Circuit Design Images of the electronic components used in the project Tools and Other Materials Used for the Project Parts of the Circuit The project’s circuit consists of two main parts: the power supply and the water level controller. Power Supply The power supply is responsible for converting AC to DC to provide the necessary electrical energy for the circuit to operate. This is achieved using components such as a transformer, bridge rectifier, capacitors, and voltage regulators. These components work together to ensure a stable DC voltage output, essential for the circuit’s operation. Below is the circuit diagram of the power part of the circuit Water Level Controller On the other hand, the water level controller part of the circuit includes components such as wires serving as sensors, transistors acting as switches, thyristors for current flow control, relays as contactless switches, and resistors and capacitors for managing current flow. These components work in harmony when connected correctly to create an automatic water level controller device. When the water level reaches a certain point, the sensors detect the change and send a signal to the transistors, which act as switches, allowing current to flow through the thyristor. The thyristor then controls the current flow, activating the relay to switch the water pump on or off, maintaining the water level within the desired range. By understanding and appropriately connecting these components, you can create an efficient and reliable automatic water level controller device. Below is the circuit diagram of the water level controller part of the circuit Circuit Diagram and Explanation for the project Below is the complete circuit diagram and explanation of the entire project Circuit Explanation Power Supply Design Breakdown: The circuit starts by converting household current to a usable voltage level, 5V to be precise.. Here’s how it’s done: Water level Controller Circuit Breakdown The circuit utilizes a 5V DC power supply to operate the water level controller. Initially, with no water in the tank, the AC current passes through the normally closed terminal of the relay, powering the pump (represented by an AC bulb and a motor). This indicates that water is being pumped into the tank. When the water touches the two wires at the lower threshold, current from the 5V DC flows through the water and into the base of transistor Q2 via resistor R1. This causes collector current to flow through transistor Q2 and into the anode of the thyristor. However, since the gate of the thyristor is not yet fired, it does not conduct electricity, and current does not flow through it. As the water level reaches the upper threshold of the tank and touches the two wires, current flows from the 5V DC source into the base of transistor Q1 through resistor R2. This causes collector current to flow through transistor Q1 and into the gate of the thyristor via resistor R4, firing the thyristor. Once the thyristor is fired, it conducts, allowing current to flow from its anode to cathode. This current biases transistor Q3, causing collector current to flow through the relay, energizing it. The relay then switches its common (com) terminal from the normally open (NO) to the normally closed (NC) terminal, cutting off the current supply to the pump and stopping water from pumping into the tank. As the water level drops below the upper threshold, the current supply to the thyristor’s gate is cut off. However, since a thyristor continues to conduct even after the firing current is removed, the relay remains energized, and the pump remains off. When the water level falls below the lower threshold, the current to the thyristor’s anode is cut off. This causes the current to the transistor that drives the relay to be cut off as well. With transistor Q3 no longer conducting electricity, the relay de-energizes, returning to its default state. This action allows AC current to flow into the pump, turning it on and restarting the water flow into the tank. This cycle continues as long as there is a power supply, ensuring a continuous water level in the tank. Below is the physical circuit on a breadboard If you’re interested in undertaking this project and need the components used in it, feel free to reach out to us for procurement. Additionally, if you require

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