i am new to this electronics and im trying to drop the voltage from a transformer down to 3 volts to run an electric shaver, my question is which would be the best way to do this a resister, or would i need to build a small circuit??
any advice welcomed
Jonny
right the transformer just has a live and neutral output on it which is at 6 volts DC
The razor needs 3V DC so i need to reduce the voltage somehow i wont ned a bridge rectifier as its already DC current coming from the transformer, i do have a multimeter it's a fluke 112true rms meter but how do i measure the current needed to run the shaver do i run it throught the meter I,E neutral from transformer, to neutral on meter, then live from the meter to the neutral on the razor?
Sorry if this is a silly question but ive forgotten more thn i used to know because i havnt messed with electronics for about 4 years now so be gentle please, lol
Cheers
Jonny
you can make a thing called a "shunt regulator" it consists of 1 resistor and 1 zener diode! if you can find out what the current draw is on the razor, i can help you choose what resistor and zener diode to use!? there are other options of course, but it all comes down to how many parts you want to use and how you are going to assemble your voltage regulator!?
To read Voltage with your multimeter, make sure the mode switch is set to AC or DC VOLTS, that the red/black leads are plugged into the normal + - jacks, and put the leads ACROSS the voltage being measured.
To read Current, make sure that the mode switch is set to AC or DC AMPS, that the red lead is move to the appropriate jack, and put the meter IN SERIES with either wire powering your shaver.
To read Voltage with your multimeter, make sure the mode switch is set to AC or DC VOLTS, that the red/black leads are plugged into the normal + - jacks, and put the leads ACROSS the voltage being measured.
To read Current, make sure that the mode switch is set to AC or DC AMPS, that the red lead is move to the appropriate jack, and put the meter IN SERIES with either wire powering your shaver.
when you say in series you mean have one wire going straight to the razor and the other wire going through the meter dont you?, i've just done that and its hardly pulling any current at all 0.001 -0.003, what would you suggest now??? im well stuck here? thanks for the advice though it's starting to come back to me now!!!
I have a transformer that has got 3, 4.5, 6, 7.5, 9, 12 on it but thats from something else so i thought id make one but its prooving harder than i first thought!! lol
Was the razor running when you measured the current? If not, then maybe you are reading the current that is going to charge the battery built-in to the razor.
Was the razor running when you measured the current? If not, then maybe you are reading the current that is going to charge the battery built-in to the razor.
Yes the razor was running what happened was i tried to plug it into the wall in the bathroom and it blew the charging circuit so ive taken that out and just put my wires straight onto the motor, its only a small one like in a hand held fan Etc so i cant imagine it needing much current to run but like i said thres no insides in the razor now just wires to the motor, i just need to make a circuit to drop the voltage by 3 volts then i can just use it like a normal one instead of a rechargable one, i shoul have really checked before i plugged it in but its too late now init lol!!
I have a transformer that has got 3, 4.5, 6, 7.5, 9, 12 on it but thats from something else so i thought id make one but its prooving harder than i first thought!! lol
Do you want to use next to no parts and spend low $ on it? does it say anything about current or voltage on the back of the shaver??? or the transformer you want to use???
Do you want to use next to no parts and spend low $ on it? does it say anything about current or voltage on the back of the shaver??? or the transformer you want to use???
i think the transformer im trying to use is from a cordless phone i used to have it says 6v 100mA 0.9va on it and the razor says 12v 400mA which i should have read before i plugged it into the mains, cost doesnt really matter its more a case of just being able to do it for my own satisfaction.
i think the transformer im trying to use is from a cordless phone i used to have it says 6v 100mA 0.9va on it and the razor says 12v 400mA which i should have read before i plugged it into the mains, cost doesnt really matter its more a case of just being able to do it for my own satisfaction.
i think it does need 3V because there was two 1.5V AA rechargable batteries inside when i took the charging circuit out and if i put and more than 6V to it, it goes too fast ( faster than it did before i killed it) i think the 12V refers to the charging circuit thats all
i think it does need 3V because there was two 1.5V AA rechargable batteries inside when i took the charging circuit out and if i put and more than 6V to it, it goes too fast ( faster than it did before i killed it) i think the 12V refers to the charging circuit thats all
well can you use your other transformer and set it to 3volts and see if it works ok? if so read the current draw, and we will take it from there!? hows that sound?
i've just connected it up like it showes in that schematic link you sent and the current draw is 0.03 thats using 3 volts from the adjustable powerpack which is 300mA,
Thanks for your patience mate
Jonny