1 Answer
The term **"three main voltages"** can refer to different things depending on the context—such as electrical power systems, electronics, or household wiring. Below are the three most common interpretations, explained clearly:
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### **1. In Electrical Power Distribution (AC Systems):**
The **three main voltages** typically refer to:
#### **High Voltage (HV)**
* **Definition:** Voltages above 35,000 volts (35 kV).
* **Used for:** Long-distance transmission of electrical power (e.g., across cities or countries).
* **Examples:** 110 kV, 220 kV, 400 kV.
* **Reason:** Higher voltages reduce power loss over long distances due to lower current.
#### **Medium Voltage (MV)**
* **Definition:** Voltages between 1,000 volts (1 kV) and 35,000 volts (35 kV).
* **Used for:** Distribution from substations to local transformers.
* **Examples:** 11 kV, 22 kV, 33 kV.
#### **Low Voltage (LV)**
* **Definition:** Voltages below 1,000 volts.
* **Used for:** Final delivery to homes and businesses.
* **Examples:**
* **230V (Single-phase)** – Common in homes (Europe, Asia, etc.)
* **120V (Single-phase)** – Used in North America
* **400V (Three-phase)** – Used in industries or commercial setups
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### **2. In Electronic Systems:**
Here, the three common voltages refer to DC supply levels used in circuits:
#### **+5V**
* Traditional logic level for TTL (Transistor-Transistor Logic).
* Used in older microcontrollers, USB power.
#### **+3.3V**
* Used in modern low-power digital electronics, microcontrollers, and sensors.
* Compatible with many ARM-based microcontrollers and IoT devices.
#### **+12V**
* Common in computer power supplies, motors, and automotive systems.
* Powers things like fans, disk drives, and some analog components.
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### **3. In Household Wiring (Single/Three-phase):**
Depending on your region:
#### **Single-phase Supply (Domestic)**
* **120V or 230V** for household appliances.
* 2 wires: Live (Hot) and Neutral.
#### **Three-phase Supply (Industrial/Commercial)**
* **400V or 415V line-to-line** (in many countries).
* 3 wires (or 4 including Neutral).
* Balanced power distribution, used for motors and large loads.
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### ✅ Summary Table:
| Context | Voltage 1 | Voltage 2 | Voltage 3 | Purpose |
| --------------------- | ------------ | -------------- | ----------- | --------------------------------- |
| Power Systems (AC) | High Voltage | Medium Voltage | Low Voltage | Transmission, distribution, usage |
| Electronics (DC) | +5V | +3.3V | +12V | Logic, sensors, motors |
| Household Wiring (AC) | 120V/230V | 400V/415V | — | Residential and industrial power |
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Would you like a diagram showing how these voltage levels fit into a power distribution system or electronic circuit?
---
### **1. In Electrical Power Distribution (AC Systems):**
The **three main voltages** typically refer to:
#### **High Voltage (HV)**
* **Definition:** Voltages above 35,000 volts (35 kV).
* **Used for:** Long-distance transmission of electrical power (e.g., across cities or countries).
* **Examples:** 110 kV, 220 kV, 400 kV.
* **Reason:** Higher voltages reduce power loss over long distances due to lower current.
#### **Medium Voltage (MV)**
* **Definition:** Voltages between 1,000 volts (1 kV) and 35,000 volts (35 kV).
* **Used for:** Distribution from substations to local transformers.
* **Examples:** 11 kV, 22 kV, 33 kV.
#### **Low Voltage (LV)**
* **Definition:** Voltages below 1,000 volts.
* **Used for:** Final delivery to homes and businesses.
* **Examples:**
* **230V (Single-phase)** – Common in homes (Europe, Asia, etc.)
* **120V (Single-phase)** – Used in North America
* **400V (Three-phase)** – Used in industries or commercial setups
---
### **2. In Electronic Systems:**
Here, the three common voltages refer to DC supply levels used in circuits:
#### **+5V**
* Traditional logic level for TTL (Transistor-Transistor Logic).
* Used in older microcontrollers, USB power.
#### **+3.3V**
* Used in modern low-power digital electronics, microcontrollers, and sensors.
* Compatible with many ARM-based microcontrollers and IoT devices.
#### **+12V**
* Common in computer power supplies, motors, and automotive systems.
* Powers things like fans, disk drives, and some analog components.
---
### **3. In Household Wiring (Single/Three-phase):**
Depending on your region:
#### **Single-phase Supply (Domestic)**
* **120V or 230V** for household appliances.
* 2 wires: Live (Hot) and Neutral.
#### **Three-phase Supply (Industrial/Commercial)**
* **400V or 415V line-to-line** (in many countries).
* 3 wires (or 4 including Neutral).
* Balanced power distribution, used for motors and large loads.
---
### ✅ Summary Table:
| Context | Voltage 1 | Voltage 2 | Voltage 3 | Purpose |
| --------------------- | ------------ | -------------- | ----------- | --------------------------------- |
| Power Systems (AC) | High Voltage | Medium Voltage | Low Voltage | Transmission, distribution, usage |
| Electronics (DC) | +5V | +3.3V | +12V | Logic, sensors, motors |
| Household Wiring (AC) | 120V/230V | 400V/415V | — | Residential and industrial power |
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Would you like a diagram showing how these voltage levels fit into a power distribution system or electronic circuit?