Current and voltage measurement. Voltmeter and ammeter.
I welcome all readers to our website and today, as part of the “ Basics of Electronics ” course, we will study the basic methods of measuring current, voltage and other parameters of electrical circuits. Naturally, basic measuring instruments such as voltmeter and ammeter .
Safety precautions
It's easy to check the current strength. It is enough to connect the multimeter in accordance with the operating rules. It is necessary to follow the instructions in order not to violate safety precautions:
- The device is connected in a de-energized state.
- Pre-inspect the insulation on the wires. With a long service life, its integrity is compromised. There is a possibility of receiving an electric shock.
- You only need to measure amperes while wearing rubber gloves.
- Measurements are prohibited in rooms with high humidity. Moisture has high electrical conductivity. The risk of injury increases several times.
- Anyone who has suffered an electric shock, regardless of its power, must be urgently taken to the nearest medical center. It is forbidden to work with electricity alone. In an emergency, your partner can call an ambulance.
- It is strictly forbidden to work with devices that spark or are broken when connected to analog power sources, for example, to a battery, batteries or power supply. All this can lead to electric shock. Not too strong, but capable of harming the human nervous system and heart.
- It is forbidden to use a multimeter after an impact, just as it is forbidden to glue it with tape or insulating tape. It is better to use a new device or entrust it to a specialist for repair and testing for suitability.
You might be interested in Measuring current with a multimeter
After using the multimeter device, the cables that were cut are connected with the circuit de-energized.
Damage is corrected with electrical tape
A multimeter is a device that is simply impossible to do without in everyday life and other areas. Having even the most minimal knowledge of its operation, you can repair the devices. Knowing the indications, it is easy to determine their unsuitability.
Current measurement. Ammeter.
And we'll start by measuring the current. The device used for these purposes is called an ammeter and it is connected in series to the circuit. Let's look at a small example:
As you can see, here the power supply is connected directly to the resistor. In addition, the circuit contains an ammeter connected in series with a resistor. According to Ohm's law, the current strength in this circuit should be equal to:
We obtained a value equal to 0.12 A, which exactly coincides with the practical result shown by the ammeter in the circuit
