Pages: 1 2 [3] 4 5   Go Down
Author Topic: transistor switch logic . very hard to solve this scenario.  (Read 3285 times)
0 Members and 1 Guest are viewing this topic.
United Kingdom
Offline Offline
Tesla Member
***
Karma: 220
Posts: 6587
Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law.
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

The resistors go the other way round (470 ohm to the lower transistor, 100 ohm to the upper transistor), and both the 1.5V and the 3.5V need to be increased to 5V if you want to feed about 3.5V to the motor.
Logged

Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

Queens, New York
Offline Offline
Faraday Member
**
Karma: 67
Posts: 2945
"Of all the things I've ever lost, I miss my mind the most" -Ozzy Osbourne
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Yes but swap the resistors around, and provide 5volts (not 1.5v) to the base and 6-9volts(not 3.5v) to the actual power source.

Edit: dc42 beat me to it.
Logged

Created Libraries:
NPV2 (NewPasswordV2),  TFT_Extension, OneWireKeypad, SerialServo.
Will provide libraries if asked in PM or forum.

isabela, philippines.
Offline Offline
Jr. Member
**
Karma: 1
Posts: 62
if you dont go, you will never know.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

The resistors go the other way round (470 ohm to the lower transistor, 100 ohm to the upper transistor), and both the 1.5V and the 3.5V need to be increased to 5V if you want to feed about 3.5V to the motor.

thanks for the help, but my problem is in the robots motor. it only has lower than 4v i think for its dc motor, and i want to amplify it to a bigger volts. and replacing its motor to a bigger motor,. 6v motor.

pls help me. read my past post for more info. thanks.
Logged

jaylisto

Queens, New York
Offline Offline
Faraday Member
**
Karma: 67
Posts: 2945
"Of all the things I've ever lost, I miss my mind the most" -Ozzy Osbourne
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Can you show us a picture? What is this motor in, does it have its own housing, holding it in place. You might not be able to change it.

Post a picture, that way we will have a better understanding of what your trying to do.
Logged

Created Libraries:
NPV2 (NewPasswordV2),  TFT_Extension, OneWireKeypad, SerialServo.
Will provide libraries if asked in PM or forum.

isabela, philippines.
Offline Offline
Jr. Member
**
Karma: 1
Posts: 62
if you dont go, you will never know.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Can you show us a picture? What is this motor in, does it have its own housing, holding it in place. You might not be able to change it.

Post a picture, that way we will have a better understanding of what your trying to do.

i want to amplify the volts produced by the line follower to power its dc motor, since its to weak to carry my sla 7v battery so i will modify my dc motor to a bigger and stronger one,. the logic of hbridge is correct but the hbridge wont work at all.






the power source of the robot is also from the sla battery.
« Last Edit: January 29, 2013, 10:24:37 pm by jaylisto » Logged

jaylisto

Queens, New York
Offline Offline
Faraday Member
**
Karma: 67
Posts: 2945
"Of all the things I've ever lost, I miss my mind the most" -Ozzy Osbourne
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Those motors are going to require a lot of current, your best bet now would be to get a actually Hbridge board. http://item.mobileweb.ebay.com/viewitem?itemId=251080674810&index=1&nav=SEARCH&nid=83702557639
Logged

Created Libraries:
NPV2 (NewPasswordV2),  TFT_Extension, OneWireKeypad, SerialServo.
Will provide libraries if asked in PM or forum.

isabela, philippines.
Offline Offline
Jr. Member
**
Karma: 1
Posts: 62
if you dont go, you will never know.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Those motors are going to require a lot of current, your best bet now would be to get a actually Hbridge board. http://item.mobileweb.ebay.com/viewitem?itemId=251080674810&index=1&nav=SEARCH&nid=83702557639

you know i cant, because im in the philippines, im in the part of the philippines where those items are not available.

i would travel far away to the capital manila to get those items.

is their any one that can help me using only basic transistors?

i think i will not found the answer any more. for ever. i am loosing my hope now smiley-cry
Logged

jaylisto

Global Moderator
UK
Offline Offline
Brattain Member
*****
Karma: 240
Posts: 24450
I don't think you connected the grounds, Dave.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Can you get hold of DPDT relays (or SPDT relays)?
Use those instead of the H-bridge.
I think I've already suggested this.
Logged

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

UK
Offline Offline
Shannon Member
****
Karma: 184
Posts: 11197
-
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

its to weak to carry my sla 7v battery

Hardly surprising - that battery is absurdly oversize for a 'bot that small. How many months were you hoping this thing would run between recharges?
Logged

I only provide help via the forum - please do not contact me for private consultancy.

Queens, New York
Offline Offline
Faraday Member
**
Karma: 67
Posts: 2945
"Of all the things I've ever lost, I miss my mind the most" -Ozzy Osbourne
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

How many transistors did you get, maybe you can double them up and make them into darlington pairs.

http://www.google.com/imgres?hl=en&safe=off&sa=X&tbo=d&biw=1440&bih=754&tbm=isch&tbnid=JwhGtXRza51_UM:&imgrefurl=http://www.opencircuits.com/Basic_Circuits_and_Circuit_Building_Blocks&docid=ByS_Bn7_5pUhSM&imgurl=http://www.opencircuits.com/images/3/30/Dtrans.png&w=500&h=356&ei=SR0JUc7iLua20AGKy4CwBw&zoom=1&iact=rc&dur=4665&sig=106574055291386674452&page=1&tbnh=178&tbnw=266&start=0&ndsp=19&ved=1t:429,r:2,s:0&tx=121&ty=88
« Last Edit: January 30, 2013, 08:18:19 am by HazardsMind » Logged

Created Libraries:
NPV2 (NewPasswordV2),  TFT_Extension, OneWireKeypad, SerialServo.
Will provide libraries if asked in PM or forum.

isabela, philippines.
Offline Offline
Jr. Member
**
Karma: 1
Posts: 62
if you dont go, you will never know.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset


what is the difference between the normal transisotr switch and a darlington connection?
Logged

jaylisto

Global Moderator
UK
Offline Offline
Brattain Member
*****
Karma: 240
Posts: 24450
I don't think you connected the grounds, Dave.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
what is the difference between the normal transisotr switch and a darlington connection?
Much higher gain
Logged

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

isabela, philippines.
Offline Offline
Jr. Member
**
Karma: 1
Posts: 62
if you dont go, you will never know.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Can you get hold of DPDT relays (or SPDT relays)?
Use those instead of the H-bridge.
I think I've already suggested this.


i searched it in google, the dpdt relay.
i think that is not possible. the dc motor continues to turn in a direction if there is no voltage in the relay...
Logged

jaylisto

isabela, philippines.
Offline Offline
Jr. Member
**
Karma: 1
Posts: 62
if you dont go, you will never know.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
what is the difference between the normal transisotr switch and a darlington connection?
Much higher gain

thanks for the fast reply.

the darlington has no resistor in the base?
Logged

jaylisto

Left Coast, CA (USA)
Offline Offline
Brattain Member
*****
Karma: 331
Posts: 16548
Measurement changes behavior
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Can you get hold of DPDT relays (or SPDT relays)?
Use those instead of the H-bridge.
I think I've already suggested this.


i searched it in google, the dpdt relay.
i think that is not possible. the dc motor continues to turn in a direction if there is no voltage in the relay...

 You need to use two relays, one DPDT to determine forward/reverse and a one SPST to to perform the stop/go command, this second relay's contacts is simply wired in series with the positive voltage coming from the motor battery.

Lefty
Logged

Pages: 1 2 [3] 4 5   Go Up
Jump to: