Elenco Electronics Projects 306-511 Instruction Manual page 5

MORE About Your Snap
Circuits ® Parts (continued)
SCR (Q3) - An SCR is a three-pin (anode, cathode
and gate) silicon-controlled rectifier diode. Like a
standard diode, it permits current flow in only one
direction. It will only conduct in the forward direction
when triggered by a short pulse (or steady voltage
applied) between the gate and cathode terminals. A
high current may damage this part, so the current
must be limited by other components in the
circuit.
The 7-segment display (D7)
devices today. It contains 7 LED's that have been
combined into one case to make a convenient
device for displaying numbers and some letters. The
display is a common anode version. That means
that the positive leg of each LED is connected to a
common point which is the snap marked "+". Each
LED has a negative leg that is connected to one
snap. To make it work you need to connect the "+"
snap to positive three volts. Then to make each
segment light up, connect the snaps of each LED to
ground. In the projects, a resistor is always
connected to the "+" snap to limit the current. A high
current may damage this part, so the current must
be limited by other components in the circuit.
7-segment Display:
(+) - power from batteries
A - Segment A
B - Segment B
C - Segment C
D - Segment D
E - Segment E
F - Segment F
G - Segment G
DP - Decimal Point
See project #337 for example
of proper connections.
MORE Advanced Troubleshooting
Elenco
If you suspect you have damaged parts, you can follow this procedure to systematically
determine which ones need replacing:
1 - 20. Refer to project manuals 1 & 2 (projects #1-101, #102-305) for testing steps 1-20, then
continue below.
21. FM Module (FM):
22. Meter (M2):
to LOW (or 10mA), the meter (M2) should deflect full scale. Then, replace
SCR:
the 10kΩ resistor (R4) with the 2.5V lamp (L1), and set the meter switch
to HIGH (or 1A). The meter should deflect to 1 or higher.
A - Anode
K - Cathode
G - Gate
is found in many
23. Recording IC (U6):
prerecorded songs.
24. Relay (S3):
on, and the green LED (D2) should be on when the switch is off.
25. Transformer (T1):
Pressing the press switch (S2) flashes the green LED
(D2). Connect the jumper wire to the CT point. Pressing
the press switch flashes the green LED.
26. Diode (D3):
light. Reverse the direction of the diode, the LED should not light now.
27. SCR (Q3):
switch (S1) and the motor (M1) should not spin. Press the press
switch (S2), the motor should start spinning. Now turn the slide
switch off and on, the motor should not spin.
28. 7-Segment Display (D7):
® is not responsible for parts damaged due to incorrect wiring.
Build project #307, you should hear FM radio stations.
Build the mini-circuit shown here and set the meter switch
Build project #308. Make an 8 second recording, then listen to the three
Build project #341. The red LED (D1) should be on when the slide switch (S1) is
Build the mini-circuit shown here.
Build the mini-circuit shown here, the red LED (D1) should
Build the mini-circuit shown here. Turn on the slide
Build project #337. All segments light, displaying the number 8.
(Adult supervision recommended)
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