- Some insulators allow heat thru, and don't conduct, for attaching heat sinks
- The Drain is sometimes the heat sink attachment.
- A crystal is --|[]|-- and a resonator is that with some caps, and a oscillator is ..
- Creates signals with constant freq
A coupling capacitor
AC ----| |----------
If it's chosen correctly, it can block any DC offset values in AC. Choose one that allows the AC feq you want thru, e.g. 1uF is a high pass filter, that will let most freq in audio range thru. You would also use a capacitor at the output pin, if you want to remove DC there.
Sometimes connect
+ ----->|----| |----- -
Sometimes connect
+ ----->|----| |----- -
| |
---\/\/\---
The voltage on capacitor is the max of Voltage, so if it starts at 5V but drops to 3V it is still 5V at the capacitor, for awhile anyway. So e.g. to have a reading over a capacitor you can measure the max voltage over the last 5 seconds for a 100uF cap, but putting in a specific resister:
X time.discharge.seconds = 5 * RC
5 = 5RC
R = 5/(5C)
R = 5/(5*100uF) 1u = 0.000001
R = 5/(5*0.0001uF)
R = 10000 = 5/0.000500
R = 10kohm
Caps with bucks and boosts, there is this info:
- The input capacitance is meant to further "smooth" the input voltage to the regulators, but the output capacitance is meant to prevent ringing and other issues within each regulator itself when it is under load
Here is a cap to provide a proper reset switch for micro from an electronic signal DTR from USB. https://electronics.stackexchange.com/questions/61537/what-is-the-cap-for-in-arduino-reset-circuit so ignore the switch in the above and just DTR and cap...
- inductor resists change in current.
- Motor is like a Inductor and R together.
- Generally you would have a diode to prevent flyback voltage, which could be -13V for a 5V fan.
<- - - - fly - - high <
---------|<------
| |
+ -----+--xxxxx--\/\/\---+---------
- - - - normal - - - >
high low
-
1uF = 0.000001F
-
1mA = 0.001A
-
High input impedance means it draws little current
-
Basic
V = IR
I = V/R
voltage * 1000 = miliamps * ohm
miliamps = (voltage * 1000) / ohm
- Power
P = IV
P = IIR
watts = amps * voltage
miliwatts = miliamps * voltage
For a transistor the voltage is the voltage dropped across the collector-emitter which is usually 0.2v. An example for 200mA of current, that is 40 miliwatts of power.
For a mosfet the R is RDSon and the current is whatever your circuit load will draw. For example a moter 1A, that is 35miliohm is 35miliwatts.
P dissaption = (max temp - ambient) / (per watt coeff)
P dissaption = 175 - 25 / 62.5 = 2.4 watts
- On off switch, or amplify small small small signals in the active region.
- BJT is used to switch motors, as they gobble up current?
- MOSFET is used for power circuits, as they grow moss.
- The metal ones are good for heat dissapation, the thru hole is for a heatsink you glue on
- Pyysics https://www.youtube.com/watch?v=AoXhq5nAGVs
- Notes
- Depletion mode acts like a closed switch top to bottom if no voltage diff between gate and source. But if you reverse the voltage like wire it wrong, it is open switch. This seems kinda like a diode to me. Depletion is drawn with no dashes.
- Enhancement mode acts like a variable resister. The symbol is an E with arrow in middle dash. The base is a L kicked over. Base=Gate Emiiter=Source Collector=Drain. D ---> S
- When voltage is applied between gate and source, high side DS current is on. When a low voltage is applied, the DS resistence is high. When some voltage the resistenace is low very low, it is RDSon and 27 mili ohm. A logical level mosfet has a VGS|VTH value of < 5v, that is, you can turn it on (resistence near zero) with less than 5v drop at V gate-source. When you apply a greater than VGS value here, no current really flows through from that side of the transister, it's just voltage.
Some characteristics of a BJT transisters (like 2N3904 TO-92 TO-220big)
some typical max voltages for wrong setup is 40 - 60v
some typical max current is 200mA
voltage dropped from collector to emitter is 0.2v
voltage dropped from base to emitter is 0.7v
current flowing into the collector is Beta * Ib
example: 100 * 4.3mA (A 5V near base + 1k ohm resister means base current 4.3mA)
current flowing out of base is Ic + Ib
a BJT NPN (high side) is normally always off, you just need to raise the Vb to > 0.7v to turn it on.
a BJT PNP (low side) is normally always on, to turn off you need to raise the Vb so that it is the same as the VCC (within 0.7v)
so if your PSU is 5V, you raise the base to 5v, then the diode is off so transistor is off. But if the VCC is 6V and you raise to 5V the transistor is still on.
so if your PSU is 6V and the trans is 0.2v, then the voltage drop across your circuit is 5.8v, so the 100 ohm motor current is I=V/R=5800/100=58mA and that is less than some example transistor maximums of 200mA
(0.7V is the min value to turn on, gnd off) A small current flowing into the base, controls a 100 times larger current flowing from Collector to Emitter. Voltage base emitter < 0.7v means it's off.
+-------------- VCC
| _
[MOTOR] flyback allow up, block down
| _
| _
V+ |/ Collector _
+----[1k]---| _
_ |\ _
_ > Emitter _
_ | _
_ | _
================================
================================
(VCC-0.7V to VCC is the min value to turn off, gnd on)
Base tied to ground controls the lager current through emitter collector. Remember to turn it off, you would need the voltage at the base to be near well enough to VCC. Some people say the current through the VCC to to base should be 1/10 the main other current, but I thought it was 1/100th .. but they both came up with 1K lol
Normal operation on is GND, but you raise it to near enough VCC and it's off.
I think you low side the stuff, so the voltages are bla, it kinda seems voltage controlled to me this one.
VCC
+--= +---------------+
| | _
| | _
or |</ Emitter _
GND --[1k]---| _
|\ _
| Collector _
| _
[MOTOR] flyback allow up, block down
| _
================================
================================
(VGS or VTH is the min value to turn on, gnd off). The voltage at the left terminal (directly at the gate! from gate to ground) it controls the current at the drain source. No current flows in the left loop, when it is on. It is on when there is a voltage.
+-------------- VCC
| _
[MOTOR] flyback allow up, block down
ThisV ..... | _
. | _
V+ G . ||-+ Drain | _
+--[R]-----+|<+ _ _
_ a |-+ ^ _
_ t | Source | _
_ e | _
_ | _
================================
================================
- The difference between the gate and source is 0, it's off (Vgate = Vsource = GND usually)
- The difference between the gate and source is +VTH, it's on (Vgate > Vsource)
- The difference between the gate and source is -VTH, it's off (Vsource > Vgate)
For depletion mode
- The difference between the gate and source is 0, it's on (Vgate = Vsource = GND usually), only when Vsource > Vgate is it off. Is this useful for anything..
(VGS or VTH getting closer to VCC is the min value to turn off, gnd on). The Vgs for on is -2 to -4v, so you turn on by setting gate to 0v .. turn off by setting the gate voltage to near enough VCC. You could use a P channel when the voltage required is still 5v, but the current required is more than an IO pin can supply, but maybe the 5v line out can supply that current? If your voltage you are turning on is 12v or so n channel is the choice.
+--= +-------------- VCC
| | _
| | _
| | | _
G |-+ Source _ _
GND--[R]-----|-> ^ _
a |-+ | _
t | Drain _
e | _
[MOTOR] flyback allow up, block down
| _
================================
================================
- The difference between the gate and source is 0, it's off (Vgate = Vsource it's off)
- The difference between the gate and source is +VTH, it's off (Vgate > Vsource it's off)
- The difference between the gate and source is -VTH, it's on (Vgate < Vsource)
For depletion mode
- The difference between the gate and source is 0, it's on (Vgate = Vsource) only when Vgate > Vsource is it off.
- Control the direction of current through circuit
- schottky drop very little voltage, like 0.2v otherwise the same. Their symbol is right angle S
- a zener diode is designed to be wired the wrong way, and has a reference voltage of x when it reaches a certain breakdown voltage. Their symbol is a slanted Z. You can't abuse them by over doing the voltage, check the power across them based on their reference voltage drop. They are written 5v1 or 3v3.
- You can add a fuse to limit current too, fuses are sometimes called PTC (positive temperature coefficient) fuse (MF-MSMF050-2) - i think it means resetable
---->|---
- They are ptype ntype, direction left to right, anode cathode (line, cathode,m is the one with the line, the blocker)
- A diode on is forward biased, V is the voltage required for it to turn on 0.7v
- off = reverse biased, Vbr is when it breaks the barrier, -100v
- An ideal diode has no voltage dropped across it
- You may need to add R to prevent the diodes from overheating in the forward bias, 1N4148 = I = 300mA is the max
- Uses: rectifier convert ac to dc
- For power, you may switch to a rectifier diode (! signal diode) that have higher max current rating
- dc = direct current, flows in one direction
- A full wave rectifier also converts the negative Vs
- A weiner is the 4 diode:
+----------+
| |
+--|<--+-->|--+ |
+ ----------+ + ==|====== -
+-->|--+--|<--+ |
| |
| |
[Circuit] |
| |
+----------+
Then to smooth the above add a low pass filter before the circuit
I have no idea on this afraid.
Short circuit is dangerous So Diodes
- ---->S----------+
- ---->S----------+ [?]
- ----------------+
# H1
## H2
### H3
#### H4
##### H5
###### H6
Alternatively, for H1 and H2, an underline-ish style:
Alt-H1
======
Alt-H2
------