# help with these circuit pls...

#### tsukaranz

Joined Aug 23, 2011
24
i badly need this one for my project...
i couldn't found anywhere on the internet...

#### tsukaranz

Joined Aug 23, 2011
24

#### bertus

Joined Apr 5, 2008
20,054
Hello,

No need for bumping.
This is an international forum, so answers can take upto 24 hours.

Bertus

#### tsukaranz

Joined Aug 23, 2011
24
i really need this thing...

#### elec_mech

Joined Nov 12, 2008
1,501
Qty Description
1x NE555 Timer IC
4x 1kΩ Resistor, 1/4W, 5%
1x 1MΩ Potentiometer, 10-turn ideal for finer control, but 1-turn acceptable
1x 10uF Electrolytic Capacitor, +/-20%, 16VDC or higher
2x 1N4001 Rectifier Diodes
2x NPN Transistors, part number depends on motor current
2x 5VDC Coil, SPDT Relays, part number depends on motor current

1x 5VDC supply capable of powering motor

#### SgtWookie

Joined Jul 17, 2007
22,201
I went on Falstad and threw together a simulation for you to experiment with:
http://www.falstad.com/circuit/#$+1+5.0E-6+10.20027730826997+50+5.0+43 165+176+176+192+176+2+5.0 c+128+352+128+400+0+3.2999999999999996E-5+0.6543065998874835 w+176+272+160+272+0 w+160+272+160+304+0 w+176+304+160+304+0 w+160+304+128+304+0 w+128+304+128+352+0 174+128+240+128+304+0+4670.0+0.5+Resistance w+128+208+176+208+0 w+128+144+240+144+0 178+416+48+480+48+0+1+0.2+0.1812730369914894+0.05+1000000.0+0.02+20.0 178+416+160+480+160+0+1+0.2+0.1812730369914894+0.05+1000000.0+0.02+20.0 g+128+400+128+416+0 g+416+160+416+176+0 R+240+144+240+112+0+0+40.0+5.0+0.0+0.0+0.5 R+416+48+416+16+0+0+40.0+5.0+0.0+0.0+0.5 w+416+48+400+48+0 w+400+48+400+80+0 w+400+80+416+80+0 w+400+192+416+192+0 w+416+96+384+96+0 w+384+96+384+208+0 w+384+208+416+208+0 d+368+208+368+160+1+0.805904783 w+368+208+384+208+0 w+368+160+400+160+0 t+352+240+384+240+0+1+0.6841293355018976+0.7280189985849131+100.0 r+304+240+352+240+0+100.0 w+384+208+384+224+0 w+384+272+384+256+0 g+384+272+384+288+0 l+544+64+544+128+0+0.01+0.049950044957540074 r+544+128+544+160+0+100.0 w+544+64+528+64+0 w+544+160+512+160+0 w+512+160+512+32+0 w+480+32+512+32+0 w+480+176+512+176+0 w+512+160+512+176+0 w+528+64+480+64+0 w+480+64+480+144+0 w+144+272+160+272+0 w+400+80+400+160+0 w+400+160+400+192+0 r+128+144+128+208+0+500.0 w+128+208+128+240+0 w+304+208+304+144+0 w+304+144+240+144+0 o+5+64+0+35+1.25+0.00625+0+-1 The values I used aren't the same as what elec_mech supplied; as this is just a simulation so that you can see something work and experiment with the values. Just in case the schematic gets lost, here's the export/import file: Rich (BB code): $ 1 5.0E-6 10.20027730826997 50 5.0 43
165 176 176 192 176 2 5.0
c 128 352 128 400 0 3.2999999999999996E-5 0.6543065998874835
w 176 272 160 272 0
w 160 272 160 304 0
w 176 304 160 304 0
w 160 304 128 304 0
w 128 304 128 352 0
174 128 240 128 304 0 4670.0 0.5 Resistance
w 128 208 176 208 0
w 128 144 240 144 0
178 416 48 480 48 0 1 0.2 0.1812730369914894 0.05 1000000.0 0.02 20.0
178 416 160 480 160 0 1 0.2 0.1812730369914894 0.05 1000000.0 0.02 20.0
g 128 400 128 416 0
g 416 160 416 176 0
R 240 144 240 112 0 0 40.0 5.0 0.0 0.0 0.5
R 416 48 416 16 0 0 40.0 5.0 0.0 0.0 0.5
w 416 48 400 48 0
w 400 48 400 80 0
w 400 80 416 80 0
w 400 192 416 192 0
w 416 96 384 96 0
w 384 96 384 208 0
w 384 208 416 208 0
d 368 208 368 160 1 0.805904783
w 368 208 384 208 0
w 368 160 400 160 0
t 352 240 384 240 0 1 0.6841293355018976 0.7280189985849131 100.0
r 304 240 352 240 0 100.0
w 384 208 384 224 0
w 384 272 384 256 0
g 384 272 384 288 0
l 544 64 544 128 0 0.01 0.049950044957540074
r 544 128 544 160 0 100.0
w 544 64 528 64 0
w 544 160 512 160 0
w 512 160 512 32 0
w 480 32 512 32 0
w 480 176 512 176 0
w 512 160 512 176 0
w 528 64 480 64 0
w 480 64 480 144 0
w 144 272 160 272 0
w 400 80 400 160 0
w 400 160 400 192 0
r 128 144 128 208 0 500.0
w 128 208 128 240 0
w 304 208 304 144 0
w 304 144 240 144 0
o 5 64 0 35 1.25 0.00625 0 -1

#### tsukaranz

Joined Aug 23, 2011
24
elce_mech:
what if i use a 3v dc motor, what is the transistor to be used??

#### SgtWookie

Joined Jul 17, 2007
22,201
The transistor won't change, but if your power supply is only 3v, you won't be able to use a BJT 555 timer, nor a relay.

#### tsukaranz

Joined Aug 23, 2011
24
The transistor won't change, but if your power supply is only 3v, you won't be able to use a BJT 555 timer, nor a relay.
can you pls, name me a generic transistor to be used...
thanks...

#### SgtWookie

Joined Jul 17, 2007
22,201
Generically, the circuit uses an NPN transistor to control the relay coil current.
More specifically, a general purpose 2N2222 transistor should work fine.

The diode can be a 1N4148/1N914 or a Schottky diode.

But you still have not told us if you are using a 3v supply for the entire project or not.

What voltages are you using for the project?
Are you using batteries? If so, what kind?

What is the current required by your motor at 3v with no load?

#### SgtWookie

Joined Jul 17, 2007
22,201
Well, perhaps you can use a resistor in series with the motor to limit the current. Otherwise, you'll likely burn it up pretty quickly. Without knowing what the required current is, it'll be kind of difficult to calculate the resistor. Perhaps once you have the motor on hand, you can figure it out by powering it from a couple of AA batteries in series.

#### elec_mech

Joined Nov 12, 2008
1,501
SgtWookie - I can't say I've done much with motors, but is a 1N914 or 1N4148 going to work better (faster response) or the same as a 1N400X diode? I suggested the 1N4001 because it can handle more current and it is what I have seen on the few motors I've taken apart from other items.

tsukaranz -
I don't think you want to apply 5V to a 3V motor. A quick look at RadioShack as a simple guideline shows motors available that run from 1.5 to 3V, then they jump to 6V. This suggests your motor is designed to operate from 1.5-3VDC. Jameco shows some that run from 1-6VDC, but also shows some with a max of 4.5VDC. Running at 5VDC could have it screaming (running too fast) and may result in damage.

If you're going to use relays to control the motor, I'd suggest using 3VDC for the motor and relay output and 5VDC for everything else. You can use a LM317 adjustable voltage regulator with some resistors to drop your 5VDC down to 3VDC.

Can you supply 3VDC to the motor now and measure the current draw with a current meter?

#### tsukaranz

Joined Aug 23, 2011
24
well, i'm not sure if i can get those things at radioshack coz i'm a bit far... i'm from phils.

by the way elec_mech, thanks for the info...

#### SgtWookie

Joined Jul 17, 2007
22,201
SgtWookie - I can't say I've done much with motors, but is a 1N914 or 1N4148 going to work better (faster response) or the same as a 1N400X diode? I suggested the 1N4001 because it can handle more current and it is what I have seen on the few motors I've taken apart from other items.
I suggested the 1N914/1N4148 for the relay coil diode; as they have very short ON and reverse recovery times. The 1N400x series does not have on and off times specified; if a particular manufacturer's diodes are slow, that could lead to the destruction of the transistor.

Schottky diodes, such as 1N5817 through 1N5819 could be used; they switch on pretty quickly and have very low reverse recovery times - far faster than standard silicon diodes.

#### tsukaranz

Joined Aug 23, 2011
24
thanks elec_mech...

now, ihave an idea...

i'll be back in a few days, for my circuit..

#### elec_mech

Joined Nov 12, 2008
1,501
I suggested the 1N914/1N4148 for the relay coil diode; as they have very short ON and reverse recovery times. The 1N400x series does not have on and off times specified; if a particular manufacturer's diodes are slow, that could lead to the destruction of the transistor.
SgtWookie,

Ah-ha! Sorry, I keep forgetting the transistors are driving the relay coils, not the motor directly. Thank you for the information, I'm sure I'll put that to use in the future.

tsukaranz,

I didn't mean you needed to go to RadioShack, I was just using their website as a reference for information since they sell hobby motors similar to the one in your picture.

#### tsukaranz

Joined Aug 23, 2011
24
thank you... my circuit was done...

i'll post it later...

#### tsukaranz

Joined Aug 23, 2011
24
here's my circuit..
there's one thing i don't understand... why is it that in the square wave, there is small wave after every three waves?? how is it so??