Ammeter digital with their own hands. Digital ammeters and voltmeters

Ammeters are devices that are used to determine the current strength in a circuit. Digital modifications are made on the basis of comparators. They differ in the accuracy of the measurement. It is also important to note that the devices can be installed in a circuit with direct and alternating current.

According to the type of construction, panel, portable, and also built-in modifications are distinguished. By appointment, there are impulse and phase-sensitive devices. Selective models are singled out in a separate category. In order to more thoroughly ruin the instruments, it is important to find out the device of the ammeter.

Ammeter circuit

The conventional circuit of a digital ammeter includes a comparator along with resistors. A microcontroller is used to convert the voltage. Most often it is used with reference diodes. Stabilizers are installed only in selective modifications. Broadband filters are used to increase measurement accuracy. Phase devices are equipped with transceivers.

The model with own hands

It is quite difficult to assemble a digital ammeter with your own hands. First of all, this requires a qualitative comparator. The sensitivity parameter should be not less than 2.2 microns. The minimum resolution it is required to withstand at 1 mA. The microcontroller in the device is installed with reference diodes. The display system is connected to it via a filter. Next, to assemble a digital ammeter with your own hands, you need to install resistors.

Most often they are selected by a commutated type. The shunt in this case should be located behind the comparator. The division coefficient of the device depends on the transceiver. If we talk about a simple model, then it is used dynamically. Modern devices are equipped with ultra-precise analogs. A stable lithium-ion battery can serve as a source of stable current.

Direct current devices

A digital direct current ammeter is produced on the basis of high-sensitivity comparators. It is also important to note that stabilizers are installed in the devices. Resistors are only suitable for switching type. The microcontroller in this case is installed with reference diodes. If we talk about parameters, then the minimum resolution of the devices is 1 mA.

AC Modifications

The ammeter (digital) of an alternating current can be made independently. Microcontrollers for models are used with rectifiers. To increase the accuracy of the measurement, wideband filters are used. The shunt resistance in this case should not be less than 2 ohms. The sensitivity of the resistors must be 3 microns. Stabilizers are most often installed in an expansion type. It is also important to note that a triode is required for the assembly. Solder it directly to the comparator. The permissible error of devices of this type fluctuates around 0.2%.

Pulse measuring instruments

Pulse modifications are distinguished by the presence of counters. Modern models are produced on the basis of three-digit devices. Resistors are used only in the orthogonal type. As a rule, the coefficient of division is equal to 0.8. The error in its turn is 0.2%. The disadvantages of the devices include the sensitivity to the humidity of the environment. Also they are forbidden to use at sub-zero temperatures. It is problematic to collect the modification yourself. Transceivers in models only apply to the dynamic type.

The device of phase-sensitive modifications

Phase-sensitive models are sold at 10 and 12 V. The parameter of the permissible error in the models fluctuates around 0.2%. The counters in the devices are only of the two-digit type. Microcontrollers are used with rectifiers. Elevated humidity ammeters of this type are not afraid. Some modifications have amplifiers. If you are going to build the device, then you need a switched resistor. The source of a stable current can be a conventional lithium-ion battery. A diode is not needed in this case.

Before installing the microcontroller, it is important to solder the filter. A converter for lithium-ion will require a variable type. The sensitivity index of it is at a level of 4.5 microns. If there is a sudden drop in voltage in the circuit, it is necessary to check the resistors. The division coefficient in this case depends on the capacity of the comparator. The minimum pressure of instruments of this type does not exceed 45 kPa. Directly, the current conversion process takes about 230 ms. The clock rate depends on the quality of the counter.

Scheme of selective devices

A selective digital direct current ammeter is manufactured on the basis of comparators with high throughput. The tolerable model error is 0.3%. The devices operate on the principle of one-step integration. Counters are only used in a two-digit type. Sources of stable current are installed behind the comparator.

Resistors are of a commutated type. For the self-assembly of the model, two transceivers are required. Filters in this case can significantly improve the accuracy of measurements. The minimum pressure of the devices lies in the region of 23 kPa. A sharp drop in voltage is observed quite rarely. The shunt resistance, as a rule, does not exceed 2 ohms. The current frequency depends on the operation of the comparator.

Universal measuring instruments

Universal measuring instruments are more suitable for household use. Comparators in devices are often not set to high sensitivity. Thus, the allowable error lies in the region of 0.5%. Counters are of three-digit type. Resistors are used on the basis of capacitors. Triodes are found both in phase and in impulse type.

The maximum resolution of devices does not exceed 12 mA. The resistance of the shunt, as a rule, lies in the region of 3 ohms. The permissible humidity for the devices is 7%. The limiting pressure in this case depends on the installed protection system.

Switchboard models

Shield modifications are made at 10 and 15 V. Comparators in devices are installed with rectifiers. The permissible error of the devices is not less than 0.4 5. The minimum pressure of the devices is about 10 kPa. The converters are mainly of variable type. For self-assembly, you can not do without a two-digit counter. Resistors in this case are installed with stabilizers.

Built-in modifications

The digital built-in ammeter is manufactured on the basis of reference comparators. The carrying capacity of the models is quite high, and the permissible error is about 0.2%. The minimum resolution of devices does not exceed 2 mA. Stabilizers are used both as an expansion and pulse type. Resistors are set high sensitivity. Microcontrollers are often used without rectifiers. On average, the current conversion process does not exceed 140 ms.

Models of DMK

Digital ammeters and voltmeters of this company are in great demand. In the assortment of this company there are many stationary models. If we consider voltmeters, they can withstand a maximum pressure of 35 kPa. In this case, the transistors are of the toroidal type.

Microcontrollers, as a rule, are installed with converters. For a laboratory study, this type of device is ideal. The digital ammeters and voltmeters of this company are manufactured with protected housings.

The Toreh device

This ammeter (digital) is made with increased conductivity of the current. Maximum pressure the device can withstand at 80 kPa. The minimum permissible temperature of the ammeter is -10 degrees. The indicated measuring device is not afraid of increased humidity. It is recommended to install it near the power source. The division coefficient is only 0.8. Maximum pressure ammeter (digital) can withstand 12 kPa. The current consumption of the device is about 0.6 A. The triode is used in the phase type. For domestic use, this modification is suitable.

Device Lovat

The specified ammeter (digital) is made on the basis of a two-digit counter. The conductivity of the model current is only 2.2 microns. However, it is important to note the high sensitivity of the comparator. The display system is simple, and the instrument is very comfortable to use. Resistors in this ammeter (digital) are installed in a commutated type.

It is also important to note that they are capable of withstanding heavy loads. The shunt resistance in this case does not exceed 3 ohms. The process of transforming the current occurs rather quickly. A sharp drop in voltage can only be due to a violation of the temperature regime of the device. The permissible humidity of this ammeter is equal to as much as 70%. In its turn, the maximum resolution is 10 mA.

DigiTOP model

This digital voltmeter- DC ammeter is issued with reference diodes. The counter is provided in two-bit type. Conductivity of the comparator is at the level of 3.5 microns. The microcontroller is used with the rectifier. The sensitivity of the current is rather high. The power supply is a normal battery.

Resistors are used in a device of a commutated type. Stabilizer in this case is not provided. The triode is installed only one. Directly the transformation of the current occurs rather quickly. For domestic use this device fits well. Filters for increasing the accuracy of measurement are provided.

If we talk about the parameters of the voltmeter-ammeter, it is important to note that the operating voltage is at the level of 12 V. Current consumption in this case is 0.5 A. The minimum resolution of the presented device is 1 mA. The shunt resistance is located at 2 ohms.

The coefficient of division of the voltmeter-ammeter is only 0.7. The maximum resolution of this model is 15 mA. Directly, the current conversion process takes no more than 340 ms. The permissible error of this device is 0.1%. The system can withstand a minimum pressure of 12 kPa.