Step 16: Transferring Components: Part 1
We are going to start with the comparators again. They lend themselves to use board space efficiently on the PC board because many of the connections between the transistors allow them to be placed very close together. The easiest way to go about the comparators is to start with the same transistors we started with on the breadboard, then move on to the outer transistors and finally the three on the other side.
The two middle transistors can be placed the same exact way they were on the breadboard, same orientation and everything. The outer two transistors can be place on the board with the same orientation. Their emitters connect to the bases of the middle two so instead of placing them to the outside of the middle pair, place the in front with their emitters in the same row as the bases of the middle pair. The 10k ohm resistor can then sit nicely between the two. The current mirror pair of transistors can be placed on the same rows as the middle pair, just like on the breadboard. Positioning the third transistor is up to you. Its a good idea to place it so that the reference input will be on the side which the other comparator will be built so that the voltage divider can be placed between the two.
What's really cool about the comparators is that they are identical in layout. The only difference which supply rail gets connected at various places. What this means is that once you have one built and soldered down, you can replicate the layout EXACTLY, remember to use the right transistors though! That includes all of the solder bridges and wires.
Once you have made the comparators, you can go ahead and make the voltage divider. If you planned ahead you would have put the references beside each other. Once again the divider is easy, a resistor from Vcc to the threshold reference, a resistor from ground to the trigger reference, and a resistor connecting the reference inputs together.
The two middle transistors can be placed the same exact way they were on the breadboard, same orientation and everything. The outer two transistors can be place on the board with the same orientation. Their emitters connect to the bases of the middle two so instead of placing them to the outside of the middle pair, place the in front with their emitters in the same row as the bases of the middle pair. The 10k ohm resistor can then sit nicely between the two. The current mirror pair of transistors can be placed on the same rows as the middle pair, just like on the breadboard. Positioning the third transistor is up to you. Its a good idea to place it so that the reference input will be on the side which the other comparator will be built so that the voltage divider can be placed between the two.
What's really cool about the comparators is that they are identical in layout. The only difference which supply rail gets connected at various places. What this means is that once you have one built and soldered down, you can replicate the layout EXACTLY, remember to use the right transistors though! That includes all of the solder bridges and wires.
Once you have made the comparators, you can go ahead and make the voltage divider. If you planned ahead you would have put the references beside each other. Once again the divider is easy, a resistor from Vcc to the threshold reference, a resistor from ground to the trigger reference, and a resistor connecting the reference inputs together.
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