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I Have A Love Hate Relationship With My Electronics

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Dammit. The 2n3904-3906 And also the tip120's I have will not properly control a motor even with diodes. This sucks. The small 3904-6 ones either overheat or output nothing, and the tip120's draw so much that they completely screw over the clocking. What to do now, maybe different transistors? Small relays? Maybe mechanical cycles who the heck knows. I'm wondering if the signal is too weak from the 4017. The 555 and 4017 are powered from a 9volt so I don't know how they could be too weak but maybe that is it.
46-50, M
1
27 replies
16 views
Jul 12, 2019
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Magnolia · 26-30, F
Another annoying thing is the sound of the equelatorizer in the scromble-box of the 7480.
SpandauBallet · 46-50, M
[@462403,Magnolia] what are you up to with an adder?
Magnolia · 26-30, F
[@959183,BlackRecluse]
[image=https://photos1.similarworlds.com/00/00/00/00/01/66/01/37/Magnolia-X4ZFIqqkUL0vtpJ.jpg]
Axeroberts · 51-55, M
Use an open collector.
Axeroberts · 51-55, M
[@959183,BlackRecluse] that is right but your supply needs to be rated accordingly
SpandauBallet · 46-50, M
Tried it. I tried this about 100 times and fried 21 transistors in the process
Axeroberts · 51-55, M
[@959183,BlackRecluse] use a coil to control the in rush of current from your motor
RealtaReoite · 56-60, M
Can you post a picture of your schematic? It's not obvious to me what you are trying to do.
RealtaReoite · 56-60, M
I'm still confused. That's a CMOS 4017 Johnson Counter you're talking about, right?

Sure, it can't drive much. Certainly not a motor of any size.

What sort of motorsare you trying to drive? You have a bunch of motors, each driven one at a time from the 4017 outputs?

A TIP120 should be driven ok from the 4017 and seems like a decent motor driver for any small dc motor. What base current are you running? Being a Darlington, you don't need much.

2N3904 has a collector current rating of 200ma or something like that and might not be the normal choice in a motor drive circuit unless the motor is really tiny.
SpandauBallet · 46-50, M
[@359015,RealtaReoite] Yes, it is a decade counter. The motor is a small 1.5v to 3v dc motor out of a toy. I was able to get a mosfet functioning as it should, but if the signal is too strong for the switch, the motor stays running so I'm using a 4.7k resistor between the signal and 4017 along with a diode
SpandauBallet · 46-50, M
at 3v it does ok, at 6v i have issues.
MethDozer · 36-40, M
A SSC or a thyristor in your set up might be the ticket.
SpandauBallet · 46-50, M
[@521796,MethDozer] Is it possible to use a 555 timer as a transistor?
MethDozer · 36-40, MNudity
[@959183,BlackRecluse] A 555 IC is a set of transistors. 25 with two diodes and 15 resistors.
SpandauBallet · 46-50, M
Lmao, nudity ahaha, I figured since the 555 can generate pulses, it is also a very powerful chip for output and if I wired it right maybe it could act as a transistor
SpandauBallet · 46-50, M
I'll try some suggestions here and also put diodes on the outputs of the 4017 to prevent reverse flow
RealtaReoite · 56-60, M
[image=https://photos1.similarworlds.com/00/00/00/00/01/66/02/04/RealtaReoite-wBcFUIimLJZEzNf.jpg]

Is this what you are trying to do?

If so, I think it should work. Assuming your motor doesn't need more than 2 or 3 amps, that is (TIP120 is rated at 5 amps, I think).

First, just connect the motor to your power supply (battery or whatever) and make sure it runs and your power source is adequate to drive it.

Then hook up the motor drive transistor but connect the base resistor to the power supply instead of the 4017. Make sure the motor runs and that nothing gets hot.

Then connect the base resistor to the 4017 and hook up whatever else is connected to the 4017.

You shouldn't need anything other than the base resistor between the 4017 and the drive transistor, though if you ever have issues with the motor coming on when it shouldn't or staying on, you could add a 10K resistor between base and emitter of the transistor to take care of any leakage currents.
MethDozer · 36-40, M
[@359015,RealtaReoite] Things always need a little tweaking between schematic and breadboard.

A zener diode in that circuit might not be a bad idea either.
RealtaReoite · 56-60, M
[@521796,MethDozer] zener where? To protect the 4017? Or???
MethDozer · 36-40, M
[@359015,RealtaReoite] No, from the transitor to the motor. Not necessary but should give the motor a little more snap when it is activated.
SpandauBallet · 46-50, M
Ok guys I have the motor functioning as it should and a fet transistor working as it should, but the really touchy area is making sure the motor is powerful enough yet also making sure the switch isn't over fed in the transistor.
SpandauBallet · 46-50, M
Unfortunately I don't have a million FET's laying around like I do the BC547's which have proven to be utterly useless in high current switching. Relays make no sense and waste energy so transistors are the answer. I just should have bought 400 fets instead of those 3904's lol
SpandauBallet · 46-50, M
I suppose theres a way to power everything off the one fet....when one pin is off in the 4017 it should be off. There's no reason I couldn't channel all outputs into one fet right?
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Dammit. The 2n3904-3906 And also the tip120's... | I Have A Love Hate Relationship With My Electronics | Similar Worlds