electronics workbench issues

[timtalk]

Hi i'm very new to electronics and still trying to learn. In order to save time and money I thought I'd use electronics workbench to try out some simple circuits and see if they work. I'm getting weird results tho from simple circuits that seem to run fine till I flip a few switches in the design then I get errors like trouble with node $15 yet I can't see how there is any errors. Would one of you be so kind as to take a look at this and see what i've done wrong?

 

[ikalogic]

I am not quite sure, but what i first noticed is the transistor, it is not well configured, the collector is no connected to anything, and Diode D1 is off..

Also i don't see what the switchies at the top left do?

Maybe if you tell us more about this circuit, we can help more, because i can't really understand its function.

but as i said i guess the transisitor is missused.

 

[captaincaveman]

Hi i'm very new to electronics and still trying to learn. In order to save time and money I thought I'd use electronics workbench to try out some simple circuits and see if they work. I'm getting weird results tho from simple circuits that seem to run fine till I flip a few switches in the design then I get errors like trouble with node $15 yet I can't see how there is any errors. Would one of you be so kind as to take a look at this and see what i've done wrong?

its a problems with the wires, for some reason you have to have the wires set up for dc, then it should work click on all wires and right click properties and tick box saying nodeset for dc. when i first used this program i made a simple circuit of battery, switch and bulb just to see how it worked and had same error couldnt work it out why there was a problem on such a simple circuit then i changed wires to nodeset for dc and problem solved

 

[timtalk]

captiancaveman I have already done as your saying and that did fix many of the errors. This circuit is a super simplified version of the real circuit i've been working on for a long time. The switch in the lower left corner represents the internal switch of a Pic. i.e. when it is closed it provides current to the transistor and when open it allows it to float (which unless i'm mistaken is how the pic does it). As for the switches in the top right corner they represent a single switch that I have (can't remember the correct electrical term for it) but it's a 3 position switch position one connects pins 1 and 3 together. Position 2 connects pins 2 and 3 together and position 3 connects pins 3 and 4 together. When J3 is closed and J4 are closed it represents the switch in position 1. If I toggle the #1 it opens J3 and closes J1 which represents position 2, by toggling #2 it opens J4 which then moves the switch into position 3. My goal is to have the relay be controlled by the PIC when in position 1, to have the relay be activated always when in position 2 and to have the relay be deactivated when in position 3. I've accomplished this with this circuit but if I toggle the switches more than just a few times (sometimes just one time) the program errors with the above mentioned error. I'm just wondering why it would do this and how I can correct my circuit to still achieve my goals yet have the program not complain after a few cycles of the J4 switch (it seems that if J4 is closed I can toggle the others without a problem).

 

[timtalk]

Any ideas?

 

[ikalogic]

As of your circuit, in general, i think there are many simpler ways to achive your goal,

As of the program, i can't help you, cause i don't know this program.

But honnestly i think there are simple ways, specially if you are using a pic...

i attached a simple version that should work, if you can afford using a standard 3 positions switch, but sure you will have to make some hanges to apply it to the style of your program!

 

[timtalk]

As of your circuit, in general, i think there are many simpler ways to achive your goal,

As of the program, i can't help you, cause i don't know this program.

But honnestly i think there are simple ways, specially if you are using a pic...

i attached a simple version that should work, if you can afford using a standard 3 positions switch, but sure you will have to make some hanges to apply it to the style of your program!

Ikalogic Thanks I think that will work all I have to do now is to figure out how to add some indicator LED's to the circuit so that I can have them indicate which mode it's in. I do have one other question tho can you explain what the resistor is used for? from what I can see it will always be connected to ground in the lower 2 positions. Guess I just don't understand it's purpose. Thanks.

 

[ikalogic]

the resistor is a PULL UP resistor,

When the transistor is ON, it provides 0V to the Relay, to turn it ON, in case the transistor is OFF, the pull up resisitor will privide 12V to trun off the relay (no current will flow)

With out the pull-up resistor, a short circuit would occure when the transistor is ON, killing the transisitor.

 

[Nigel Goodwin]

the resistor is a PULL UP resistor,

When the transistor is ON, it provides 0V to the Relay, to turn it ON, in case the transistor is OFF, the pull up resisitor will privide 12V to trun off the relay (no current will flow)

With out the pull-up resistor, a short circuit would occure when the transistor is ON, killing the transisitor.

Sorry 'ikalogic', but that's completely incorrect - the resistor isn't needed in the circuit, and does nothing useful at all.

 

[Hero999]

If you want to add a resistor, put one in series with the diode so the relay turns off faster, use the same value as the relay's coil resistance.

 

[timtalk]

Thanks Nigel I thought I was really lost, I even spent an hour reading over pull up resistor examples trying to figure out how this was a required/needed resistor.

Hero999 thanks for the suggestion I've added a 2ohm resistor in series like you suggested.

Now all I have to do is figure out how to make LED lights indicate which position the switch is in.

 

[Nigel Goodwin]

Thanks Nigel I thought I was really lost, I even spent an hour reading over pull up resistor examples trying to figure out how this was a required/needed resistor.

Hero999 thanks for the suggestion I've added a 2ohm resistor in series like you suggested.

Now all I have to do is figure out how to make LED lights indicate which position the switch is in.

Should be VERY simple, but I'm still quite confused by what you're trying to do, the simulator circuit (as opposed to a 'real' circuit) doesn't make it very clear.

In ikalogic's much clearer circuit you could put a resistor and LED (in series as normal) across the transistor, so it lights when the transistor is OFF, or across the relay coil to light when the transistor is ON.

 

[timtalk]

Well the basic idea is that the +5 volt source is actually the output from a pic and that output drives a relay which controls pumps, lights etc (all A/C items). I want to be able to place a 3 position switch (which i've already purchased) into the circuit which when in position 1 a green led is on and the relay is contolled by the pic. In position 2 the relay is always on reguardless of the pic's condition and a Yellow LED is on. In position 3 a RED led is on and the relay is off reguardless of the pics condition. I.e. it's an override switch with visual indicator of the switch conditon. I'm not dead set yet as to if I want the green led to come on and off with the pics condition when in position 1 or if I want the LED to be always on if the switch is in position 1 (i'll probably settle for which ever method I can achieve). Hopefully this clears up what i'm wanting to do. I tried to draw this out in electronics workshop and found that I was having a lot of issues with it erroring out. Thus I started to make the circuit more and more simple to see what was causing the issues. By adding a pull down resistor to the base of the NPN's I've pretty much been able to remove all the errors (still get a few here and there at random).

 

[Nigel Goodwin]

The switching is VERY simple to do, place your switch between the relay and the collector of the transistor - common of the switch to the relay, you should be easily able to figure the rest out!. For the LED's use a double pole switch, and use the other pole to switch the LED's.

 

[timtalk]

Nigel I agree that would be a very simple way to do it. Unfortunatly I've already purchased the switches and am sort of limited to the supplys I have. I think I have a circuit that should work (it seems to work in the Electronics Workbench) program but I had to substuite a few items like the relay. the one I'm using is a OZ-SH-112D but I belive that it should still work the same as the one I used in the simulation. Also the switch I have is a single pole 3 position switch (which there was not such a switch in the program so I just used 4 seperate switches and ensured that when I operated it in simulation mode that I only made connections that the real switch would do.) i.e. 1-3, 2-3, and 3-4. Any suggestions would be welcome. Thanks again.