diff --git a/Rob's_portion/.DS_Store b/Rob's_portion/.DS_Store
new file mode 100644
index 0000000000000000000000000000000000000000..0d44d3a9855ad71891b5f9f068aa490a204c815b
Binary files /dev/null and b/Rob's_portion/.DS_Store differ
diff --git a/Rob's_portion/amplifiers/index.html b/Rob's_portion/amplifiers/index.html
new file mode 100644
index 0000000000000000000000000000000000000000..1c36a883630989580cc673bfb19b12efc3e4f59e
--- /dev/null
+++ b/Rob's_portion/amplifiers/index.html
@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+<html>
+<title>Electronics intro:  Amplifiers</title>
+
+<xmp theme="journal" style="display:none;">
+<br>
+
+
+### Amplifiers
+
+- ####Transistor as amplifier.
+
+![picturetransistor](../images/transisto_amp.jpg)
+
+
+---
+- ####Feedback concept.  Op amp circuits.
+
+![inverting](../images/invert_amp.jpg)
+
+---
+
+- ####Microcontroller as amplifier.
+
+![micro as amp ](../images/micro_amp.jpg)
+
+
+
+
+---
+
+
+
+</xmp>
+
+<script src="../../../../strapdown/strapdown.js"></script>
+</html>
diff --git a/Rob's_portion/images/20180918_163423.jpg b/Rob's_portion/images/20180918_163423.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..90ef7c68e92ea986deb661a8c59c44c39e3a8b9d
Binary files /dev/null and b/Rob's_portion/images/20180918_163423.jpg differ
diff --git a/Rob's_portion/images/example.png b/Rob's_portion/images/example.png
new file mode 100644
index 0000000000000000000000000000000000000000..7485013d281ef9964fdf2465b3467e33c6fdd347
Binary files /dev/null and b/Rob's_portion/images/example.png differ
diff --git a/Rob's_portion/images/example2.png b/Rob's_portion/images/example2.png
new file mode 100644
index 0000000000000000000000000000000000000000..22e6ebbc1349de4feb6ccaa1809e72d21e3f82d8
Binary files /dev/null and b/Rob's_portion/images/example2.png differ
diff --git a/Rob's_portion/images/flyback.jpg b/Rob's_portion/images/flyback.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..93f17ad6f9045fc0c654877affdf88ef6e277fa6
Binary files /dev/null and b/Rob's_portion/images/flyback.jpg differ
diff --git a/Rob's_portion/images/h_bridge_chips.jpg b/Rob's_portion/images/h_bridge_chips.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..570cfda641700848fb2efc0dbf45ca150af9d8be
Binary files /dev/null and b/Rob's_portion/images/h_bridge_chips.jpg differ
diff --git a/Rob's_portion/images/h_bridge_circuit.png b/Rob's_portion/images/h_bridge_circuit.png
new file mode 100644
index 0000000000000000000000000000000000000000..15efc1e3bea5c36a0edce6ebb1d6129e539c1cf6
Binary files /dev/null and b/Rob's_portion/images/h_bridge_circuit.png differ
diff --git a/Rob's_portion/images/h_bridge_circuit_1.jpg b/Rob's_portion/images/h_bridge_circuit_1.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..b844980abbd491cdf92ab8d67058ca306ece34e9
Binary files /dev/null and b/Rob's_portion/images/h_bridge_circuit_1.jpg differ
diff --git a/Rob's_portion/images/inductor.jpg b/Rob's_portion/images/inductor.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..5d8681ee5e0d3a2df0e9e8aa44c67ef7f8adf550
Binary files /dev/null and b/Rob's_portion/images/inductor.jpg differ
diff --git a/Rob's_portion/images/inductor_circuit.jpg b/Rob's_portion/images/inductor_circuit.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..db9033b52a59ea3a0415f2774cf62fc132249ac8
Binary files /dev/null and b/Rob's_portion/images/inductor_circuit.jpg differ
diff --git a/Rob's_portion/images/inductors.jpg b/Rob's_portion/images/inductors.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..59cb54e3ca553c529880335c05e8559706e3a93f
Binary files /dev/null and b/Rob's_portion/images/inductors.jpg differ
diff --git a/Rob's_portion/images/input_pullup.jpg b/Rob's_portion/images/input_pullup.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..feafb17363def6816e977a0c9abb8128980f7235
Binary files /dev/null and b/Rob's_portion/images/input_pullup.jpg differ
diff --git a/Rob's_portion/images/invert_amp.jpg b/Rob's_portion/images/invert_amp.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..a9ba6a656494496fefb2877ed65d2148dd2e7249
Binary files /dev/null and b/Rob's_portion/images/invert_amp.jpg differ
diff --git a/Rob's_portion/images/micro_amp.jpg b/Rob's_portion/images/micro_amp.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..257d0d64922f9f7cc6da7f2d6787c1200e73b083
Binary files /dev/null and b/Rob's_portion/images/micro_amp.jpg differ
diff --git a/Rob's_portion/images/placeholder.png b/Rob's_portion/images/placeholder.png
new file mode 100644
index 0000000000000000000000000000000000000000..c1bedc6712765369ac12953ffc61ff784983d9ff
Binary files /dev/null and b/Rob's_portion/images/placeholder.png differ
diff --git a/Rob's_portion/images/t45_pinout.png b/Rob's_portion/images/t45_pinout.png
new file mode 100644
index 0000000000000000000000000000000000000000..d3e8c9abf963e161f7b6b053a7b49f23ff18ef4d
Binary files /dev/null and b/Rob's_portion/images/t45_pinout.png differ
diff --git a/Rob's_portion/images/transisto_amp.jpg b/Rob's_portion/images/transisto_amp.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..f58c5606ff15da08db97251d13c3cee6bae926d7
Binary files /dev/null and b/Rob's_portion/images/transisto_amp.jpg differ
diff --git a/Rob's_portion/index.html b/Rob's_portion/index.html
new file mode 100644
index 0000000000000000000000000000000000000000..e5144552f614947698548b7d1d393e9fcbf0c38d
--- /dev/null
+++ b/Rob's_portion/index.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<html>
+<title>Electronics 101.  How to use the components on the fab inventory.</title>
+
+<xmp theme="journal" style="display:none;">
+<br>
+
+
+## Electronics 101
+
+How do components work in circuits?  What are their symbols? What do they look like?
+Some practical considerations about power supplies and use of fab inventory
+connectors on circuitboards.  Datasheets.
+
+___
+
+###Outline.
+
+- [Inductors and motor driving.](./inductors_motors/index.html)
+
+- [microcontroller](./microcontroller/index.html)
+
+- [amplifiers.](./amplifiers/index.html)
+
+
+
+
+---
+
+
+
+</xmp>
+
+<script src="../../../strapdown/strapdown.js"></script>
+</html>
diff --git a/Rob's_portion/inductors_motors/index.html b/Rob's_portion/inductors_motors/index.html
new file mode 100644
index 0000000000000000000000000000000000000000..4b1a053e62e0c4595a911f9f6f6f59a398adf96b
--- /dev/null
+++ b/Rob's_portion/inductors_motors/index.html
@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+<html>
+<title>Electronics intro:  Inductors</title>
+
+<xmp theme="journal" style="display:none;">
+<br>
+
+
+## Inductors and motor driving
+
+-----
+
+### Inductors
+  - ####Inductors are devices that store energy in a magnetic field.  V= L*di/dt
+
+  ![picture of symbol and examples](../images/inductors.jpg)
+  ![picture of inductor circuit RL](../images/inductor_circuit.jpg)
+
+  Figure:  1.  Symbol and examples of inductors.  2.  Inductor circuit.
+
+  - ####driving inductive loads - flyback diodes.
+
+  ![picture of flyback circuit](../images/flyback.jpg)
+
+---
+
+### Motor driver
+
+- ####To drive a motor, you need to be able to switch current direction.  The usual solution is the h-bridge geometry.
+
+![picture of h-bridges](../images/h_bridge_circuit_1.jpg)
+
+![picture of h-bridges](../images/h_bridge_circuit.png)
+
+- ####Here is a module, and the chip that we will use to drive up to 3.5A of motor current.
+
+ ![picture of h-bridges](../images/h_bridge_chips.jpg)
+
+
+
+
+
+
+---
+
+
+
+</xmp>
+
+<script src="../../../../strapdown/strapdown.js"></script>
+</html>
diff --git a/Rob's_portion/microcontroller/index.html b/Rob's_portion/microcontroller/index.html
new file mode 100644
index 0000000000000000000000000000000000000000..9bcd0e8f10d3b69ae1090d974083c075fd362bfc
--- /dev/null
+++ b/Rob's_portion/microcontroller/index.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<html>
+<title>Electronics intro:  microcontrollers.  </title>
+
+<xmp theme="journal" style="display:none;">
+<br>
+
+
+## Microcontrollers.
+
+  [Datasheet](https://datasheet.octopart.com/ATTINY45-20SU-Atmel-datasheet-41301906.pdf) for ATtiny45, the small AVR microcontroller
+  in the inventory.  Other ATtiny's and ATMega's (including the Mega328P used in Arduino) are similar.
+  XMEGAs have more capabilities.
+
+
+___
+
+###Microcontrollers.
+
+As circuit elements.  Programming will be discussed later.
+
+Pins:  Supply (2.7-5.5V), ground, reset.  Other pins available for input and output.  Configured by programming to be input or output.
+
+  ![picture](../images/t45_pinout.png)
+
+  #### Input.
+
+  - Digital inputs (using VCC=5V):  Low for 0 - ~2.3 V. High for 2.3 - 5 V.
+
+  - Individual pins can be configured to have an input pullup resistor.
+  This is used, for example, to make a simple button input circuit.
+
+  ![picture](../images/input_pullup.jpg)
+  - Analog to Digital converter.  (ADC)  "Analog" input.  Uses digital process to infer analog voltage.
+  - Built-in analog amplifier.  Attiny45 has a 20X differential amplifier.
+
+#### Output.
+- Digital output.  Low, high, tri-state.
+- what can the ucontroller drive?
+  - Things with high input impedance: FETs, Piezoelectric transducers, other microcontroller inputs.
+  - To some extent, things with low imput impedance:  maximum current is 40mA per I/O pin.  Enough to (over)drive LEDs.
+  - One way to get "Analog" out:  Pulse width modulation (PWM)
+
+
+
+---
+
+
+
+</xmp>
+
+<script src="../../../../strapdown/strapdown.js"></script>
+</html>