# Voltage drop of a PWM signal

Hello so i have a microcontroller that is driving the following circuit:

Both the MCU and the circuit are powered by a 5v power supply, when PAD_PWM and PAD_PWM_return are not shorted ore there is no load between them the circuit its Drawing 6.22 mA which is correct. But when i short PAD_PWM and PAD_PWM_return with a wire i see a voltage drop from 5V to around 0.5V and the total current consumption of 18.88 mA. the duty cycle of the PWM its 50% so in theory the difference in current I'm seeing its correct as 5*.5 its 2.5V/ 200 ohm its 12.5 mA which its almost the current difference that we got from working under no load and working under load.

But i cant know for sure if that increase in 12mA its in fact going through the R10 and the wire. because I'm seeing a voltage drop, it doesn't make sense to me.

The MCU works flawlessly and it doesn't stutter or anything at all.

• " i see a voltage drop from 5V to around 0.5V" - Where? Also what frequency is the PWM, and what voltage do you measure at PAD_TREATMEN? Jun 12 '20 at 21:08
• the voltage drop its measured from PAD_PWM to PAD_PWM_return, PWM frequency its 10.81 Htz and PAD_treatment its 5v on the ON part of the PWM Jun 12 '20 at 21:55
• By '10.81Htz' do you mean 10.81 (ie. ~11) pulses per second? What was the measured voltage at PAD_TREATMENT with 50% PWM? Jun 12 '20 at 22:09