# Diodes Question

Hello,
I am using some diodes in a project that incorporates small vibrating motors. The strange thing is when I measure the voltage (without hooking up the motors) if measure just before the diode the voltage is correct 5V when i measure after the diode te voltage appears 6.5V! how is this possible? i would expect a drop in voltage not a raise!
any ideas why?

Can you explain (tough without a diagramme) how the psu and diode is wired, and where you're measuring the voltage etc.?

Probably inductive kickback. Thatâ€™ll get you in inductive circuits like relays, solenoids, and motors. Probably nothing to worry about if you have a diode in there. Many people choose to put a diode across the device in order to shunt any kickback.

Kyle

Well, he mentioned motors, and anything with a core and lots of turns of wire tend to produce kickback when the field collapses. Although I haven't personally tried getting kickback from a motor, I have seen it first hand from relays and solenoids.

A waveform from a 'scope would be a great help at this point. That'll let us know right way where the 6.5V is coming from.

Kyle

I am sorry for my late reply I am coming back with a proper schematic in a while thnx guys!

I take power from an Arduino Diecimila. My diode is a 1N4001 1A/50V. When I measure the voltage of arduino then (A circuit) I get 4.99 V. When I create a circuit like the B then the reading in my meter is around 6.3 V.

a multimeter: UNI-T UT30B :-/

the Arduino is working properly and I am taking power from a USB I am going to try what u suggest

I did use a resistor 9K ohms in parallel with the meter and I measure 4.45V

Thanx Richard it drove me crazy that thing especialy since it was showing an extra 2 Volts :-) I am in the middle of project with a quite tight deadline and I have to tackle all sort of things and that was in the middle of everything totally absurd! thanx again!