From a1d98dd10a24c56e91628ae04bd4e9f7ffeff26b Mon Sep 17 00:00:00 2001 From: Robert Hart <hart@physics.harvard.edu> Date: Thu, 20 Sep 2018 11:37:53 -0400 Subject: [PATCH] rob's changes 005 --- basic_concepts/index.html | 51 +++++++++++++++++++++++++++------------ 1 file changed, 36 insertions(+), 15 deletions(-) diff --git a/basic_concepts/index.html b/basic_concepts/index.html index d43518e..956b451 100644 --- a/basic_concepts/index.html +++ b/basic_concepts/index.html @@ -227,17 +227,17 @@ A good starting point for newcomers in the electronics field looking for what is ### Capacitors - - basic concept + - ####basic concept  - - Capacitance: the ratio of charge on one of the plates of a capacitor to the voltage that exists between the plates + - ####Capacitance: the ratio of charge on one of the plates of a capacitor to the voltage that exists between the plates C = Q/V, Units: Farads, 1F = 1C/1V  - - we could content with this limited knowledge. However, if you want + - we could be content with this limited knowledge. However, if you want - to build your own capacitors - understand time-dependent behavior such as displacement current and capacitive reactance - a deeper understanding of capacitance is needed: @@ -247,25 +247,33 @@ A good starting point for newcomers in the electronics field looking for what is - A very nice Sparkfun tutorial on capacitors and their applicaitons: https://learn.sparkfun.com/tutorials/capacitors/introduction - - RC time constant. Time domain behavior. + - ####RC time constant. Time domain behavior.  - - Alternating Current in a Capacitor - - everything that is discussed about capacitors in dc circuits also applies in AC circuits with one major EXCEPTION - - DC circuit: - - block current flow (except during short time of charging and discharging) - - AC circuit: - - pass or limit current flow depending on frequency - - capacitor; stores electrical energy and returns it ot the circuit + - ####Capacitors in filters: low pass and high pass. +The charging and discharging of the RC combination makes capacitors useful as frequency filters. - - low pass (PWM to make analog out) - - high pass (coupling audio signals) - - filter capacitors on power rails. - - using capacitors as sensors +  +--- + + - ####filter capacitors on power rails. +Capacitors resist changes in voltage by virtue of their energy-storage capabilities. +We use them to absorb fluctuations in power supply voltage in almost every board that we make. +  + + --- + + - ####using capacitors as sensors + Capacitance sensing is used in many ways. During our "Input devices" week, you will see practical examples of this. + +  +  + +--- ### Transistors @@ -315,6 +323,19 @@ A good starting point for newcomers in the electronics field looking for what is - A nice tutorial on BJTs from Sparkfun: https://learn.sparkfun.com/tutorials/transistors#applications-i-switches +#### FETs + +- Field Effect Transistors. [Article](https://www.electronics-notes.com/articles/electronic_components/fet-field-effect-transistor/what-is-a-fet-types-overview.php) +A small voltage on the input, requiring essentially no current, controls a large current through the transistor. + +- Below are two of the FETs in the fab inventory. Both n-type MOSFETS. Left 1.7 amps, right 16 amps max. current. We also have p-type MOSFETS. + + +  +  + +####Relays + - Controlling high voltage power devices using transistors: https://www.instructables.com/id/Arduino-Tutorial-Handling-High-Power-Devices/ -- GitLab