Maker Pro
Maker Pro

Problems with my school project Automatic ON OFF lamp using LDR and MOSFET

kylie1023

May 26, 2023
1
Joined
May 26, 2023
Messages
1
my transformerless power supply on the left side of the volt meter works just fine until i connect it to my load circuit on the right. the volt coming out just stays 1.5V at most and i cannot figure out why, please help thank you1685099514899.png
 

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,186
Joined
Nov 17, 2011
Messages
13,186
School project? This type of "power supply" is absolutely not suitable for a school project.

Please do not use this so called "power supply" design. Although the voltage on the secondary is low, the whole circut is connected to mains and thus potentially lethal.

Throw away the power supply section and use a well insulated safe power supply, e.g. a USB wall wart. Or an adjustable wall wart for higher output voltage and power.
 

Alec_t

Jul 7, 2015
3,354
Joined
Jul 7, 2015
Messages
3,354
Welcome to maker.pro, but I agree with Harald.:eek:
i cannot figure out why
Because R10(?) prevents any significant current flow in the circuit.

What is the lamp rating?
Which MOSFET?
What are the LDR specs?
 
Last edited:

bidrohini

Feb 1, 2023
98
Joined
Feb 1, 2023
Messages
98
I agree with the first answer. I also suggest you check all the parts separately with DC voltage. See if all of them are functional.
 
Top