diff --git a/tech/Ham.wiki b/tech/Ham.wiki
index 1e8db09..bda185a 100644
--- a/tech/Ham.wiki
+++ b/tech/Ham.wiki
@@ -26,3 +26,7 @@ The following are the Public Use radio bands
 == Frequency Ranges ==
 
 see [[frequency_range]]
+
+== Electronics ==
+
+see [[electronics]]
diff --git a/tech/electronics.wiki b/tech/electronics.wiki
index 7ab8647..2e647f8 100644
--- a/tech/electronics.wiki
+++ b/tech/electronics.wiki
@@ -2,6 +2,24 @@
 
 Both digital and analog components
 
+== Properties ==
+
+_Voltage_ is the electrical potential. It is similar to water pressure in a
+pipe. Voltage is polarized, and relative, therefore it is often measured with
+respect to the earth, or _ground_. A parallel circut always has the same
+voltage across all components.
+
+_Current_ is the flow of electricity. It is similar to water flow in a pipe.
+Current is not polarized, and not relative. A series circut always has the same
+current across all components.
+
+These two are related via 
+
+== Primitive ==
+
+* [[Resistor]]
+* [[Capacitor]]
+* [[Incudctor]]
 
 == Combinational ==
 
diff --git a/tech/frequency_range.wiki b/tech/frequency_range.wiki
index 74f12d0..27af019 100644
--- a/tech/frequency_range.wiki
+++ b/tech/frequency_range.wiki
@@ -5,11 +5,14 @@ standardized. They appear below
 
 | Name | Abbreviation | Range | Notes |
 ---------------------------------------
-| Very Low Freq   | VLF | 3khz - 30khz   |                  |
-| Low Freq        | LF  | 30khz - 300khz |                  |
-| Medium Freq     | MF  | 300khz - 3mhz  | AM Radio         |
-| High Freq       | HF  | 3mhz - 30mhz   | Shortwave        |
-| Very High Freq  | VHF | 30mhz - 300mhz | VHF TV, FM radio |
-| Ultra High Freq | UHF | 300mhz - 3ghz  | UHF TV, 3G/4G    |
-|                 |     |                |                  |
+| Very Low Freq     | VLF | 3khz - 30khz   |                  |
+| Low Freq          | LF  | 30khz - 300khz |                  |
+| Medium Freq       | MF  | 300khz - 3mhz  | AM Radio         |
+| High Freq         | HF  | 3mhz - 30mhz   | Shortwave        |
+| Very High Freq    | VHF | 30mhz - 300mhz | VHF TV, FM radio |
+| Ultra High Freq   | UHF | 300mhz - 3ghz  | UHF TV, 3G/4G    |
+| Super High Freq   | SHF | 3ghz - 30ghz   |                  |
+| Extreme High Freq | EHF | 30ghz - 300ghz |                  |
+
+