TIMER WITH
RELAY
INSTRUCTION SHEET
Price - Stock No 270
Check Your
Kit
Schematic Diagram
PCB Layout
To print the Board refer to Printing Circuit Boards.
- Mounting the components is relatively easy.
The resistors will have to have the legs
bent to match their holes, and can go in any way round. The IN914
(little glassy diodes) and the IN4002 diode all have
bands on the body which must be
put in the direction shown on the drawing. A magnifying
glass will help to locate the bands. They can be
soldered off as you go if you wish.
- The transistor has a flat on the body which must be in
the direction shown on the drawing.
- The electrolytic capacitors (C2) are polarised. The
arrow on the body must be to the negative rail - the bottom track
of the PCB. The greencaps are not polarised so they can go in any way
round.
- The LED also must be polarised. Look
for the small flat on the flange below the globe
and put this as shown on the sheet.
- Push the legs of the trimpot into
the three holes and solder. PLEASE NOTE
THAT IF THE TRIMPOT IS A HORIZONTAL (BLUE COLOURED) TYPE it is different from
the upright (flat, silver coloured) one. For
the horizontal type BEND ONE OUTSIDE LEG UP UNDER THE BODY SO IT
DOES'NT TOUCH THE TRACK and SOLDER TWO ONLY LEGS
IN PLACE - one outside leg and the centre leg.
- If you are fitting a Potentiometer then the
mounting is by flying leads to the
same three locations as for the trimpot, viz. two
poles (centre and one outside) to one track and the other outside
pole bridging across to the other track.
- The molex pins are to connect
the push-button switch and the battery snap to the circuit. Push them
through their holes from the back of the board and solder. Make
sure you get a good bond with the solder. Cut the red wire of the
battery snap and solder the slide switch in this line. The wires should
be joined to the centre pole, and to one end pole ON THE
SAME SIDE AS THE WIRE ON THE CENTRE POLE. (Double pole double throw -DPDT -
Switch).
- The relay fits to the board with five legs, all of
which must be soldered. Some slight bending of the
legs may be necessary to adjust to the holes. Please Note that the relay
is activated by the battery driving the timer, but a separate supply is
required for switching. The diagram shows the points where
this circuit is connected to the relay. The Relay
has a 5 AMP. rating so a
fairly wide range of switching applications is possible.
- Care should be taken to avoid bridging across between
the legs of the 8 Pin IC Socket with solder. Use a fine tip and just
enough solder to make a good bond. Plugging in the 555 Timer IC should
be the last thing you do to the board.
There is a locating DOT on the plastic body at one end. This must go to
where the drawing indicates by the word DOT. If you do not have an IC
insertion tool, the legs will have to
be squeezed together a bit to fit into the
socket. Lie four legs on a flat surface and apply enough pressure to
distort them inwards a little. Repeat this until
the IC legs start into their
sockets. Push home firmly after making sure all the legs are correctly
positioned.
- Connect a 9VOLT battery. To test your timer it is best
to turn the rotor of the trimpot
clockwise to its lowest setting to give
the minimum time lapse, then switch the slide switch on. Nothing should
happen. Press the push button switch and the LED should light, and the
timing cycle begin. The LED will turn off when the time has
expired. Test through the range of settings of the trimpot.
Calibration is best done when you have mounted the timer in a
box and you have designed and made an external control
mechanism to adjust the trimpot.
TROUBLE SHOOTING
Troubleshooting will involve checking
locations, polarity and soldering of all components.
Meticulous care when building the project will avoid time
consuming and frustrating trouble shooting.
Contact CdS electronics
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