Slotted Optical Switch

[felto]

Has anyone ever heard of this switch?

It looks like a 'U' shape and has four terminals
to it soldered to the circuitboard. In between
the 'U' shape is a grove where something blocks
the optics and I guess that it turns it on or off.

My question is does anyone know how to measure
this with a voltmeter? I know there are diodes
inside to measure for .6 volts or something but
can someone tell me which terminals to test
and what readings should I get. Thanks in advance

 

[MP1]

Felto,
Perform a search for opb optical switches. Here is a link to an application note:
http://www.optekinc.com/pdf/App%20Note%20213.pdf#search='opb%20optical%20switch'

One side has an LED and the other side has a photo transistor. Making or breaking the light path turns the transistor on or off. They are good for indicating that something is moving or to measure RPM when used with a slotted wheel.

MP

 

[felto]

Thanks

Do you know how to test a voltage regulator?

I have a 7812CT 3-pin voltage regulator
and I think its bad. Can you tell me
what pins are what and how to test
it with a voltmeter? Its for a multiprinter
gizmo and when I hook up the power it sparks
back and I get no juice from it. Thanks again
for your help

 

[MP1]

Felto,
This is a new subject. You should start a new topic or others might not read your question.
Here is the data sheet for the 7812. It has the pin out and the electrical characteristics. Basically, the middle pin is ground and the right pin is the 12 volt output when you give the left pin enough voltage. Please see the data sheet to make this more clear.

MP

LM78XX.pdf

 

[felto]

but can I test the leads just like I would
test a diode?

 

[MP1]

For this type of testing. everything in the circuit will effect the readings unless you pull the device and test it. This is not necessary. If you lift pin 3 to insure something else in the circuit is not pulling down the voltage, and then you measure 14.6 volts or more between pins 1 and 2 but do not measure 12 volts or close between pins 3 and 2, I would suspect a bad voltage regulator. However, if you do find 12 volts between pin 3 which is lifted and pin 2, the ground, then something else in the circuit is pulling down the voltage.
Note: Power should be turned off while you are desoldering the pin. Then turned back on for the test.

MP