In order to test power supplies, there is an electronic load. This device works on the principle of signal generation. The main parameters of the modifications include the threshold voltage, the allowable overload, and the dissipation factor. There are several types of devices. In order to understand the loads, it is first of all recommended to familiarize yourself with the device diagram.
Modification scheme
Standard load circuit includes resistors, rectifier and modulator ports. If we consider low frequency devices, then they use transceivers. These elements work on open contacts. Comparators are used to transmit the signal. Recently, loads on stabilizers have been considered popular. First of all, they are allowed to be used in a DC network. They have a fast transformation process. It is also worth noting that an integral element of any loadconsidered an amplifier and a regulator. These devices are closed on the plate. They have a fairly high conductivity. It is the modulator that is responsible for the generation process of the models.
Modification types
Distinguish between impulse and programmable devices. In a separate category, laboratory ones are allocated, which are suitable for powerful power supplies. Also, modifications differ in the frequency with which they work. Low-frequency loads are equipped with transistors with a channel adapter. They are used on AC power. Models of high-frequency type are made on the basis of an open thyristor.
Pulse devices
How is a pulsed electronic load made? First of all, experts recommend choosing a good thyristor for assembly. In this case, the modulator is suitable only for two phases. Experts say that the expander should work alternately. Its operating frequency should be approximately 4000 kHz. The transceiver is installed into the load through a modulator. After soldering the capacitors, it's worth working on the amplifier.
For stable operation of the load, three channel directivity filters are required. A tester is used to test the device. The resistance should be approximately 55 ohms. With an average load, a home-made electronic load produces a rated voltage in the region of 200 watts. Comparators are used to increase the sensitivity. When the system closes, it is worth checking the circuit from the capacitor. If the resistance on the contacts is underestimated, then the transceiver needs to be changed to a capacitive analogue. Many experts point to the possibility of using wave filters, which have good conductivity. Regulators for these purposes are used on the triode.
Programmable Models
The electronic programmable load is fairly easy to assemble. For this purpose, an expansion transceiver for 230 V is used. Three contactors are used to transmit the signal, which depart from the transistor. Regulators are used to control the conversion process. Linear analogs are most often used. The triode is used with an insulator. In this case, you will need a blowtorch. The resistor is directly fixed on the transceiver.
Regular comparators, which have a low dissipation factor, are definitely not suitable for the model. It is also worth noting that many make a mistake when they install one filter. For normal operation of the prior, only capacitive analogues are used. The nominal voltage at the output should be approximately 200 V with a resistance of 40 ohms. If you assemble devices on a single-junction expander, then linear models are not suitable.
First of all, the device will not work due to a large overload of the thyristor. It is also worth noting that the model will require a line modulator with low sensitivity. Some specialists use stabilizers when assembling. If we consider a simple modification, then an adjustable type is suitable. However, inverting elements are most often used.
Lab modifications
Laboratory is being assembleddo-it-yourself electronic load with a powerful thyristor. Resistors are used with a capacitance of 40 pF. Experts say that only expansion type capacitors can be used. Particular attention during assembly should be paid to the modulator. If you use a wired analog, then the load will require three filters. A simple electronic load has a phase-type modulator with a conductivity of 30 microns. The resistance is approximately 55 ohms. It is also worth noting that loads are often stacked based on a switched transceiver. The main feature of such devices lies in the high pulsation. In this case, conductivity is provided at around 30 microns.
FET device
The electronic load on the field effect transistor is made only on the basis of a comparator, and the thyristor is used of an adjustable type. When assembling, first of all, it is worth choosing a capacitor unit, which plays the role of a pulse generator. In total, three filters are required for the modification. The resistor is installed behind the plates. Experts say that the electronic load on the field effect transistor produces a resistance of 40 ohms.
If the conductivity is greatly increased, then a capacitive capacitor is installed. It is recommended to use the transceiver directly with two contacts. The relay is installed as standard with the regulator. The rated voltage for loads of this type is not more than 400 watts. Experts say that the lining should be fixed behind the resistor. If we consider the high-frequency model for300 V power supplies, then the modulator will need a wave type. In this case, a tetrode is installed behind the thyristor.
Model with continuously adjustable current
The electronic load circuit with smooth current control includes one thyristor. Capacitors for the model will require an expansion type with low conductivity. It is also worth noting that one amplifier is put into the load. The most commonly used wave analogues, which have a phase adapter. The regulator is directly installed behind the modulator, and the rated voltage should be about 300 W.
A simple electronic load with continuously adjustable current has two contactors to connect. Thyristors can sometimes be used on plates. Comparators in devices are installed with and without stabilizers. In this case, much depends on the operating frequency. If this parameter exceeds 300 kHz, then it is better not to install a stabilizer. Otherwise, the scattering coefficient will increase significantly.
TL494 based device
The TL494 based electronic load is pretty easy to assemble. Resistors for modifications are selected in line type. As a rule, they have a high capacity. And they are able to work in a DC network. When assembling the model, the thyristor is used on two plates. Electronic pulse load based on TL494 works with a phase or pulse type expander.
The first option is the most common. The rated voltage of the loads starts from 220 watts. Filters are of the full type, and the conductivity is no more than 4mk. When installing a regulator, it is important to evaluate the output impedance. If this parameter is not constant, then an amplifier is used for the model. Contactors are installed with and without adapters. The output voltage in the circuit is approximately 300 watts for loads. When devices are turned on, the current often rises. This happens due to the heating of the modulator. The user can avoid this problem by lowering the sensitivity.
100W Models
Electronic load (diagram shown below) for 100 W involves the use of two channel thyristors. The transistor in models is quite often used on an expansion basis. It has a conductivity of about 5 microns. It is also worth noting that there are loads on the relay. They are best suited for powerful power supplies. For self-assembly, wave comparators are additionally used. Home-made devices give out a voltage of no more than 300 V, and the operating frequency starts from 120 kHz.
200W units
The 200 W electronic load includes two pairs of thyristors, which are connected in pairs. Many models use wired low frequency comparators. It is also worth noting that a modulator is required to assemble the modification. Amplifiers are used to speed up the signal generation process. These elements can only work from wired filters.
The transceiver should be installed behind the plates. In this case, the load voltage is approximately 400 V. Specialistthey say that devices on wired transceivers do not work well. They have low conductivity, there are problems with overheating. If voltage surges are observed, it is worth changing the comparator. Another problem may be the resistor.
How to make a 300W device?
300 W electronic load involves the use of two phase-type thyristors. The rated voltage of the devices is approximately 230 watts. The overload factor in this case depends on the conductivity of the comparator. If you assemble this device yourself, you will need a channel-type modulator. A blowtorch is used to install the element.
Regulators are often used with an adapter. The relay is installed low-resistance type. The dispersion coefficient for a homemade modification is approximately 80%. It is also worth noting that the contactors used are of low sensitivity. How to check the load before switching on? You can do this with a tester. The output voltage for homemade devices is usually 50 ohms. If we consider models with one comparator, then this parameter may be underestimated.
Models for 10 A units
The electronic load for the 10 A power supply is collected using an expansion thyristor. Transistors are quite often used at 5 pF, which have low conductivity. It is also worth noting that experts do not recommend using linear analogues. They have little sensitivity. They greatly increase the dissipation factor. Contactors are used to connect to the unit. modulators quite oftenused with adapters.
If we consider the circuit on the capacitor unit, then their frequency is on average 400 kHz. In this case, the sensitivity may change. Contactors are quite often fixed behind the modulator. Stabilizers should be used on two plates. It is also worth noting that a pole resistor is required to assemble the modification. It greatly helps to increase the speed of pulse generation.
Devices for 15 A units
The most common loads are for 15 A units. They use open resistors. In this case, the transceivers are used with different polarity. In addition, they differ in sensitivity. On average, the voltage of the devices is 320 V. The models differ in conductivity from each other. For the purpose of self-assembly, comparators are used on regulators. Stabilizers are attached before starting their installation.
Specialists say that expanders can only be installed through the lining. The input conductivity must be no more than 6 microns. When installing the regulator, the comparator is carefully cleaned. If you assemble a simple model, then the modulator can be used as an inverter type. This will greatly increase the dispersion coefficient. The threshold voltage is on average 200 V. The permissible power parameter is no more than 240 W. It is also worth noting that filters of different types are used for the load. In this case, much depends on the conductivity of the comparator.
Device diagram for 20 A blocks
Electronicload (diagram shown below) for 20 A units is based on binary resistors. They maintain stable high conductivity. The sensitivity in this case is approximately 6 mV. Some modifications are distinguished by a high overload parameter. Relays for models are used on wave transistors. Comparators are used to solve conversion problems. Expanders are often of the phase type. And they can have several adapters. If necessary, the device can be assembled independently. For this, a capacitor unit is used.
The rated voltage for homemade loads starts at 300 W, and the average frequency is 400 kHz. Experts do not advise the use of transient comparators. Regulators are used with plates. An insulator is required to install the comparator. If we consider loads on two thyristors, then filters are used there. On average, the capacitance of the module is 3 pF. The dispersion index for homemade models starts from 50%. When assembling the device, special attention should be paid to the adapter for connecting to the power supply. Contactors are selected pole type. They must withstand large overloads and not overheat.
AMETEK devices
Loads of this brand are distinguished by low conductivity. They are great for 15 A power supplies. Among the models of this company, there are many pulse modifications. Their individual overload is not high, but a high pulse generation rate is provided. SpecialistsFirst of all, they note the good security of the elements. They use several filters. They deal with phase noise that distorts signals.
If we consider high frequency models, they have several thyristors. It is also worth noting that there are modifications on wired comparators on the market. Based on the usual load of this brand, you can assemble an excellent device for different power supplies. The models have excellent stabilizers and very sensitive transistors.
Features of the Sorensen series
The standard electronic load of this series includes a thyristor and a linear comparator. Many models are made with pole filters that are capable of operating at high frequencies. It is also worth noting that laboratory modifications are on the market. They have a fairly low dispersion coefficient. Models are quite often used of the switched type. The overload indicator is on average 20 A. Protection systems are used in different classes. There are impulse models on store shelves. They are well suited for testing computer power supplies. Expanders in devices are used with plates.
ITECH series models
Loads of this series are distinguished by high conductivity. They have good security. In this case, multiple transceivers are used. The electronic load for the power supply operates on average at a frequency of 200 kHz. In this case, the overload is 4 A. Amplifiers in devices are used with contact adapters. Thyristors are used of phase or code type. Among the models of this series there are programmable modifications. They are well suited for testing computer power supplies. Transceivers can be found with or without expanders.
Loads based on IRGS4062DPBF
Making an electronic load with your own hands based on this transistor is quite simple. The standard scheme of the model includes two capacitor units and one expander. It should be noted right away that models of this class are well suited for 10 A power supplies. The voltage parameter for loads is 200 W. Filters for devices are selected low frequency. They are able to work under heavy loads.
First of all, when assembling, a thyristor is installed, and a different type of comparator can be used. The transistor is directly installed using a soldering iron. If its conductivity exceeds 5 microns, then it is worth installing a dipole filter at the beginning of the circuit. Experts say that the electronic load on the IRGS4062DPBF transistor can be done with transient comparators. However, they have a high dissipation factor.
It is also worth noting that the models in this series are only suitable for DC circuits. The allowable overload parameter of devices is 5 A. If we consider devices on pulse comparators, then they have a lot of advantages. First of all, the high frequency catches the eye. At the same time, the resistance of the devices shows at the level of 50 ohms.
They have no issues with conduction and power surges. Stabilizers allowedapply different types. However, they must operate in a DC circuit. There are also modifications without capacitors on the market. Their dispersion coefficient is approximately 55%. For devices of this class, this is very small.
KTC8550 based devices
Transistor database loads are highly valued among professionals. Models are great for testing small power units. The allowable overload indicator is usually 5 A. Models may use different protection systems. When assembling the modification, it is allowed to use binary modulators with a conductivity of 4 microns. Thus, devices will output a higher frequency at 300 kHz.
If we talk about the shortcomings, it is worth noting that the modifications are not able to work with 10 A power supplies. First of all, there are problems with impulse surges. Overheating of the capacitor will also make itself felt. To solve this problem, expanders are installed on the loads. Triodes are usually used with two plates and an insulator.
