From 364399d85f7c4ef196a8396e92cf66fae7383525 Mon Sep 17 00:00:00 2001
From: Tyler Perkins <tperki17@kent.edu>
Date: Mon, 15 Nov 2021 15:45:01 -0500
Subject: [PATCH] Update for 15-11-21 15:45

---
 tech/ADC.wiki | 16 ++++++++++++++++
 tech/DAC.wiki |  9 +++++++++
 2 files changed, 25 insertions(+)
 create mode 100644 tech/DAC.wiki

diff --git a/tech/ADC.wiki b/tech/ADC.wiki
index 37ccff7..8b4ea77 100644
--- a/tech/ADC.wiki
+++ b/tech/ADC.wiki
@@ -6,5 +6,21 @@ This is also known as sampling.
 
 == Overview ==
 
+=== Parallel ===
+
 1) Analog voltage is converted to a codeword, by running the voltage through a
    series of comparators, each tied to a different voltage
+2) The series of codewords are put through a series of logic gates that convert
+   the code words to a n-bit value, ranging from 0V to VREF
+   - ie. VREF = 5V, 10-bit ADC, each step is 5/(2^10) = 4.9mV
+
+This is a very fast way to implement a ADC, however for a n-bit resolution it
+requires 2^n - 1 comparators, and 2N resistors (for voltage dividers) to
+convert the signal
+
+=== Counting ===
+
+1) Compare the analog input voltage to an output from a [[DAC]]
+2) Each time a comparison fails, increment a counter
+3) When the [[DAC]] voltage is larger than the analog voltage, we have found the
+   correct value
diff --git a/tech/DAC.wiki b/tech/DAC.wiki
new file mode 100644
index 0000000..2eeb6b0
--- /dev/null
+++ b/tech/DAC.wiki
@@ -0,0 +1,9 @@
+= DAC =
+
+A Digital to Analog Converter (DAC) is a type of circut that converts a digital
+signal to a voltage somehwere between GND and VREF (usually VCC). A common
+use of a DAC is when converting digital music to a sound signal
+
+== Overview ==
+
+1) A voltage divider (resistors in series) split the VREF into equal parts