Small adjustable constant voltage electronic load

A low-power constant-voltage electronic load with a temperature-controlled fan, with a maximum power of about 30W.

A constant voltage electronic load is a device used to test a constant current power supply. A common application scenario is to test whether the battery charger is reliable, such as testing the maximum output current of the purchased lithium battery charger, the voltage of the turning light, etc. Or it can be temporarily used as an adjustable linear voltage regulator.

characteristic:

• The constant voltage value is adjustable from 0 to 27V. This range can be modified simply by changing the resistance of the voltage dividing resistor.
• The maximum power is about 30W
• Full plug-in design, components are cheap and easy to obtain. The structure is simple and can even be welded on the perforated board by yourself.
• Implementing a simple linear temperature control speed fan through N-MOSFET

Note: For common constant voltage power supplies, constant voltage electronic loads, if the set voltage is lower than the power supply voltage, it is equivalent to a short circuit, and if it is higher than the power supply voltage, it is equivalent to an open circuit, so do not use it to test the constant voltage power supply. Common power supplies are constant voltage power supplies. To test the constant voltage power supply, a constant current electronic load must be used. Here is a project link ****

PCB physical diagram, P1 interface is used to connect a three-wire voltmeter :

Welding actual picture:

Solution verification board prototype

Comparison between solution verification board and physical board

Constant voltage 3.7V, input current 1A operation effect

Constant voltage 3.7V input 2A current operation effect: