Note: this project should be used together with the project :https://www.pcbway.com/project/shareproject/Electronic_Active_Dummy_Load_PCB2_2_Logic_Board_613dc175.html

The active electronic load consists of two modules:

- the analog module (the one shown here)

- digital module with Atmega328 - Electronic Active Dummy Load_PCB2/2 (Logic Board)

Proposed parameters for the prototype: 0-50V, 0-10A, 250W.

The load has two operating modes: constant current mode and constant resistance mode.

For superior performance, special attention had to be paid to cooling. The digital module adds more comfort in use because it manages the thermal regime and alerts the user or even cuts off the power supply in critical situations.

Please see: https://www.pcbway.com/project/shareproject/Electronic_Active_Dummy_Load_PCB2_2_Logic_Board_613dc175.html

This module can be used independently of the digital module, switching on/off the output and changing the working modes using switches. The disadvantage is that the management of the task parameters is the responsibility of the user. The prototype of the project was built using the two modules and works very well, as a result I recommend choosing this solution.

The active load has two operating modes:

• constant current mode
• the constant resistance mode

Each of these regimes can be used depending on the type of test to which the DC source being tested is subjected.

First, it must be adjusted to the maximum current for each of the two regimes. Exceeding the value of 10A is a risk assumed by the user, the load being designed for this maximum current value.

The first step is the test supply of the assembly with a voltage of 12V DC to one of the connectors J1 and J3. Two pairs of connectors were provided to meet the needs of connecting and placing the active load modules in the housing. Ditto for the sword-type connectors marked with LOAD.

The test source is adjusted to have a low output voltage, e.g. 12V, and, if it has current limitation, the current is adjusted to the maximum.

To connect the test source to the active load, one of the two pairs of spade connectors marked LOAD on the analog wiring can be used.

Adjusting the maximum current for the constant current operating mode

The ADJUST potentiometer is brought to the zero position. Place a strap between pins 2 and 3 of JP1_1 and increase the current from the ADJUST potentiometer little by little, over time up to a value of 10A (or a lower value if desired). If the current does not reach the desired value, it is adjusted from R2. Likewise if the current exceeds the desired maximum value (10A in the example from this material). The semi-adjustable R2 practically adjusts the upper limit of the current, rotating in one direction the current value will increase and in the opposite direction it will decrease.

Adjusting the maximum current for the constant resistance operating mode

The ADJUST potentiometer is brought to the zero position. In this case, the strap is placed on pins 1 and 2 of JP1_1. The maximum current limit will be adjusted similarly as before using in this case R27.

For a fine adjustment of the maximum current value, it is good to use multi-turn semi-adjustable for R2 and R27.

The functioning of the prototype built by me can be seen in the following clips:

https://www.youtube.com/watch?v=mFIV7O4Ulko

https://www.youtube.com/watch?v=ntBzmWfZGSo&t=11s