Newbie looking for a switching circuit

Thread Starter

JGrad

Joined Jul 14, 2019
8
Hi Experts. First post - so hope I'm in the right place?

I'm looking for a circuit that from research I think is a multivibrator circuit. I tried to build a circuit with a 555 timer but think I blew it up as nothing happened.

I want to be able power two small electro-magnets alternately so that a small metal shaft inside both of the magnets can be pulled from one to the other as power to each electro-magnet is connected and then disconnected in turn. Hope this makes sense. I would also like to be able to control the speed with which the shaft moves from one to the other which I thought would be the switching speed and also the strength of the magnets, which I thought might be the power to the magnets.

Would this circuit be possible for a beginner? I made two electro-magnets and had the shaft moving from one to the other manually with on off switches but failed on automating it.

Any help would be greatly appreciated.

Many Thanks

Jack
 

MaxHeadRoom

Joined Jul 18, 2013
19,163
You could build one of the original bi-polar transistor flip flops, that WE had to do before IC's, ;)but that may work for you. Google flip-flop.
Do you want it automatic switching or manual?
Max.
 

Thread Starter

JGrad

Joined Jul 14, 2019
8
You could build one of the original bi-polar transistor flip flops, that WE had to do before IC's, ;)but that may work for you. Google flip-flop.
Do you want it automatic switching or manual?
Max.
Hi Max
Thanks for the reply
I wanted it to work automatically with being able to adjust the speed and the strength of the magnets
Regards
Jack
 

Thread Starter

JGrad

Joined Jul 14, 2019
8
LOL - Oh dear. I checked Flip Flop Circuits in Wiki - I got lost in the computer jargon. Is that why they went to IC's :)
Jack
 

Bernard

Joined Aug 7, 2008
5,285
It may be possible to slow the rod with pulse width modulation, PWM. I would stick with 555's with drivers
What is the purpose ? You could configure as a steam engine & the rod would move back & fourth?
 

Thread Starter

JGrad

Joined Jul 14, 2019
8
Thanks for the interest everyone.
I used a two 6V lantern batteries with two small plastic tubes closed at one end wrapped with copper wire. Switching each one on and off in turn caused the shaft to move from one tube to the other.
I'm trying to create a small bell chiming system where the shaft moves between two bells at the speed and strength that I select.
I see the flipflop circuit but was struggling to see how to incorporate the speed in each direction and strength
Many thanks again.
 

be80be

Joined Jul 5, 2008
1,941
Too make a bell all you need is one coil a spring and one rod
The spring swings the rod back to hit one bell the coil drives the rod to hit the other bell
This shows a lever but you could use a coil and rod and spring like a door bell does

 

Alec_t

Joined Sep 17, 2013
10,438
I tried to build a circuit with a 555 timer but think I blew it up as nothing happened.
Electromagnets are inductors, which generate very high voltages when current through them is switched off. This high voltage needs to be suppressed (usually with a reverse-biased diode connected in parallel with the coil) to prevent damage to the switching device (the 555).
If your coil drew more than 200mA or so, that too could have damaged the 555.
 

Thread Starter

JGrad

Joined Jul 14, 2019
8
Hi
Thanks for the suggestion. I had examined a bell to see this working but my problem as I explained, is that I need to be able to vary the speed with which the shaft moves from side to side and also stop it completely when necessary.
I also wanted to vary the strength of the magnets but I'm sure I can do that by varying the voltage to the magnets?
Many thanks again for the help.
 

Thread Starter

JGrad

Joined Jul 14, 2019
8
Hi Alec
In my naiveté I had thought that the circuit I'm looking for could alternately control two relays to open and close and that each relay would control an electromagnet's separate circuit. That way I could also control the strength of each magnet separately.
Many thanks for replying
Jack
 

Alec_t

Joined Sep 17, 2013
10,438
I had thought that the circuit I'm looking for could alternately control two relays to open and close and that each relay would control an electromagnet's separate circuit.
Bear in mind that relay coils are also inductors, so require voltage spike suppression.
 

Thread Starter

JGrad

Joined Jul 14, 2019
8
Thanks Alec. I'm sure that's excellent advise.
Unfortunately, I've no idea how start even the basic circuit I need, let alone voltage spike suppression :)
 
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