My original LED and Relay question

[Peter]

For anyone who tried helping me, you wasted your time.

I found out what my problem is - I don't know how to read a transistor data
sheet and understand which leg is which.

I assumed the picture was showing the pin diagram from the top of the
transistor (with the legs on the bottom of the transistor), however, it was
showing it with the legs facing up.


Another words: my transistor is in backwards.


After doing all this research as to why my relay wouldn't work, I came
across two specs I don't understand for the DSP1-DC5V.

It states a pick-up voltage of 4 volts (max) and a drop out voltage of 0.5
volts (min).


To me, that states the relay needs a maximum of 4 volts to turn on and will
remain on until reduced to 0.5 volts. If it's a 5 volt relay, then the 4
volts should state "minimum".

 

[Palindrome]

For anyone who tried helping me, you wasted your time.

I found out what my problem is - I don't know how to read a transistor data
sheet and understand which leg is which.

I assumed the picture was showing the pin diagram from the top of the
transistor (with the legs on the bottom of the transistor), however, it was
showing it with the legs facing up.


Another words: my transistor is in backwards.

Someone suggested that you had reversed c and e, IIRC.

After doing all this research as to why my relay wouldn't work, I came
across two specs I don't understand for the DSP1-DC5V.

It states a pick-up voltage of 4 volts (max) and a drop out voltage of 0.5
volts (min).


To me, that states the relay needs a maximum of 4 volts to turn on and will
remain on until reduced to 0.5 volts. If it's a 5 volt relay, then the 4
volts should state "minimum".

If you apply an increasing voltage to the relay coil, the maximum
voltage that you need to apply to ensure that the relay is turned on is
4 volts. The minimum voltage that can cause one of these relays to turn
on will be somewhat less..

 

[Peter]

Someone suggested that you had reversed c and e, IIRC.


If you apply an increasing voltage to the relay coil, the maximum
voltage that you need to apply to ensure that the relay is turned on
is 4 volts. The minimum voltage that can cause one of these relays to
turn on will be somewhat less..

Well I measured the Vbe and had 0.7 volts and triple checked the
drawing. But you're correct, someone suggested it and it was the
problem.

I've never understood the concept of a transistor being x2 diodes. The
base to emitter diode is understandable, but the collector "diode" has
its anode on the base and the cathode on the collector.

Is it theoreticaly a zener diode then? I always assumed the collector
diode faced into the base, however, that's not the case.

About the relay spec. I would think they'd spec it as: Minimum pick-up
voltage (or turn on voltage) is X volts. This way I know if I apply X
volts to its max, it will turn on.

 

[Palindrome]

Well I measured the Vbe and had 0.7 volts and triple checked the
drawing. But you're correct, someone suggested it and it was the
problem.

I've never understood the concept of a transistor being x2 diodes. The
base to emitter diode is understandable, but the collector "diode" has
its anode on the base and the cathode on the collector.
?

http://www.kpsec.freeuk.com/components/tran.htm




Is it theoreticaly a zener diode then? I always assumed the collector
diode faced into the base, however, that's not the case.

Nope, it's two diodes. But it isn't two independent diodes, as lots of
diagrams show it.

About the relay spec. I would think they'd spec it as: Minimum pick-up
voltage (or turn on voltage) is X volts. This way I know if I apply X
volts to its max, it will turn on.

That would mean that you need 4 volts, as a minimum, to operate the
relay. Which is untrue - many of these relays will pull in at less than
that. The minimum turn on voltage is possibly going to be around
3.4volts.. But the maximum you need to operate the relay is 4 volts..

 

[Rubber Glover]

For anyone who tried helping me, you wasted your time.

I found out what my problem is - I don't know how to read a transistor
data
sheet and understand which leg is which.

I assumed the picture was showing the pin diagram from the top of the
transistor (with the legs on the bottom of the transistor), however, it
was
showing it with the legs facing up.


Another words: my transistor is in backwards.


After doing all this research as to why my relay wouldn't work, I came
across two specs I don't understand for the DSP1-DC5V.

It states a pick-up voltage of 4 volts (max) and a drop out voltage of 0.5
volts (min).


To me, that states the relay needs a maximum of 4 volts to turn on and
will
remain on until reduced to 0.5 volts. If it's a 5 volt relay, then the 4
volts should state "minimum".

Are you the goatse man ?