RuiDeng LD25 User manual

Ruideng Technology Co. Ltd.
- 1 -
Instructions for USB Intelligent electronic load
-Model: LD25/LD35
Dear Customer,
Thank you for purchasing this USB electronic load from Hangzhou Ruideng Technologies Co.,
Ltd. Prior to using this product we recommended that you briefly familiarize yourself with these
instructions. In order to ensure the correct operation and use of the device. We also advise that
you keep these instructions in a safe place for future reference as may be needed.
NOTE:
This product has no reverse connection protection, the input polarity cannot be
reversed, otherwise the product is permanently damaged and cannot be repaired.

Ruideng Technology Co. Ltd.
- 2 -
Technical Parameters:
Product Model
LD25
LD35
Rated operational voltage
DC4-25.0V
Max discharging power
25W
35W
Rated operational current
0.25-4.00A (when fan don’t
work, the minimum constant
current is 0.05A )
0.25-5.00A (when fan don’t
work, the minimum constant
current is 0.05A )
Fan Speed
Oil bearing intelligent
temperature control fan ，
speed 5800±10%RPM
Hydraulic bearing intelligent
temperature control fan ，
speed 8000±10%RPM
Application
Application suggestions: Charger, power supply and other
device manufacturers want long-term discharge or batch
aging test of products, please choose LD35 (LD25 is not
applicable)
Constant current resolution
±（1％+3 digits）
Heat dispatch method
Intelligent temperature control fan + All aluminum fan
Working temperature
-10℃-40℃
Adjustable potentiometer
Precision multiloop adjustable potentiometer
Display mode
4 bit LED tube
Expansion port
Micro USB port、Type-C port
Product weight
About 57g
Product size
84x41x28mm
Note: Description taking an example of LD25, other applicable models ar
e universal.
Product Structure

Ruideng Technology Co. Ltd.
- 3 -
A. Micro USB port：MAX current 2A
B. USB male port (widened power wire，MAX current 4A）
C. Type-C port：MAX current 4A
D. All aluminum heat sink
E. Intelligent temperature control fan
F. 4 Bit LED tube
G. Precision multiloop adjustable potentiometer
H. “SET” button：press “SET” to switch display status, Press and hold the button to set the load
output recovery mode after protection removed.
I. “ON/OFF” button: press the button to open or close output. Press and hold the button to set
the boot default status of open or close.
Function Introduction:
a. Protection function:
OVP (over-voltage protection): there is OVP at 25-30V; it will
be damaged permanently over 30V.at OVP, LED show OVP,
as picture 1 show)
OTP(over-temperature protection): load temperature is over
80℃, the LED show OTP, as picture 2 show.
OPP(over-power protection): the power is over 25W, the LED
show OPP, as picture 3 show.
b. Set output recovery mode after load entering protection status,
manual or automatic
c. View the voltage value, current value and power value of the
load.
d. Intelligent temperature control fan. When the power is over 10W or the temperature is over
40℃, the fan will start.
e. Precision multiloop adjustable potentiometer: you can adjust the current precisely, upto
0.01A. so you don’t need to adjust a big current mistakenly to damage the power supply. So
the power supply will not be damaged due to mistakenly adjustment
f. you can set default boot status freely, open or close.
Operation Instruction
The load is powered at the range of 4-25.0V (the input polarity cannot be reversed, otherwise
the product is permanently damaged and cannot be repaired), the LED will be flashing to
remind current setting value, waiting for output. Press ON/OFF button, open output to start
work.
1. Adjust output current value.
Turning the rotary control clockwise increases the value and anticlockwise decreases the value.
According to the needs of the situation, the potentiometer can realize coarse adjustment or
fine adjustment. The fine adjustment can be accurate to 0.01A.
2, Adjust LED display status
Press “SET” to adjust the LED display status, default display output current value. Press “SET”

Ruideng Technology Co. Ltd.
- 4 -
button to display *.**A、**.*P、**.*V followed by recycling.
3. Open or close load output
Press “ON/OFF” button, you can open or close load output
4, Set load default boot status (open or close status, Factory default close status)
Press and hold “ON/OFF” button to set load default boot status freely. Press and hold
“ON/OFF” button, if the LED will display “--ON”, as picture 4, the load will open output when
power on next time; If the LED display”-OFF”, as picture 5 show,
the LED will display current value flashing at last shutdown
when power on next time, then press “ON/OFF” button to open
output.
5, Set the load output recovery mode after protection removed.
Press and hold “SET” button to set output recovery mode after
protection removed. Press and hold “SET” button, if the LED will
display “--ON”, as picture 4, and the protection was removed,
the load will recover to work; If the LED display”-OFF”, as picture 5 show, and the protection
was removed, the LED still show protection status, then press “ON/OFF ‘button, the display
will display present setting current flashing, then press “ON/OFF‘ button again, the load
recover to work.
NOTE: Please check the output current of power bank carefully. The current of the general
power bank is generally small, so adjust smaller current when the load was used.
Application
Assist to measure Micro USB cable good or not
Assist to measure Type-C cable good or not
Assist to measure output current capacity of charger good or not
The usage of large batch ageing test at the charger factory