Search found 1531 matches

by dyarker
Fri Jun 14, 2019 1:59 pm
Forum: General Discussion
Topic: Mini amp circuit
Replies: 147
Views: 204557

Re: Mini amp circuit

?? AB?? Both Q5 and Q6 are NPN.

Only Q4 is PNP. It does not need a negative supply. It's collector is toward the most negative which in this case circuit common. And the base can go negative RELATIVE to the emitter.

Cheers,
by dyarker
Thu Jun 06, 2019 9:26 am
Forum: General Discussion
Topic: 1N457 need equivalent
Replies: 12
Views: 2104

Re: 1N457 need equivalent

Use 1N4148 to replace a 1N457.

Whose support is a mess? And, says who?
by dyarker
Wed May 29, 2019 1:15 pm
Forum: General Discussion
Topic: Help with a circuit again
Replies: 5
Views: 271

Re: Help with a circuit again

bell.png
bell.png (10.96 KiB) Viewed 226 times
NPN to PNP, reverse diodes, reverse polarized capacitors, pin 1 of optocoupler stays positive.

Cheers,
by dyarker
Mon May 27, 2019 4:30 am
Forum: General Discussion
Topic: Question About Computer ATX PSU
Replies: 3
Views: 189

Re: Question About Computer ATX PSU

In Windows under "Settings" then "Power and Sleep" change Time to Sleep to "never". Some types of power supply can not regulate the logic supply (often +5V)((or 3.3V on newer)) when the current goes below a minimum. If forced to stay on, the voltage climbs till the mobo is fried. I've also heard of ...
by dyarker
Wed May 22, 2019 5:21 pm
Forum: General Discussion
Topic: Li-Po cell Id.
Replies: 13
Views: 386

Re: Li-Po cell Id.

Thanks, understand series/parallel.
by dyarker
Wed May 22, 2019 6:47 am
Forum: General Discussion
Topic: Li-Po cell Id.
Replies: 13
Views: 386

Re: Li-Po cell Id.

Tzap, Aren't the cells in series? That increases the voltage of the pack, it does not increase the AmpHours.
by dyarker
Sun May 12, 2019 2:00 pm
Forum: General Discussion
Topic: jack Question
Replies: 3
Views: 250

Re: jack Question

http://www.switchcraft.com/Documents/EDG4.pdf#page=91

That shows block without jacks. Scroll up to page 81 for start of 1/4" jacks.

0.173" more in use now.

I searched at Digikey for "1/4" jacks". Open frame may not be style want. Check page 80 for jack schematics.
by dyarker
Sat May 11, 2019 4:23 am
Forum: General Discussion
Topic: [18650] rechargeable battery + super capacitor
Replies: 7
Views: 250

Re: [18650] rechargeable battery + super capacitor

http://www.vishay.com/docs/28409/196hvc.pdf Haklesup, that looks like one RC time. I don't believe the device can operate at 1/3 of normal supply voltage. Though super caps are small enough for pocket size project. solar3000, At 160mA, I'll GUESS you'll need 3 or more (maybe 10) 45F caps to allow ti...
by dyarker
Fri May 10, 2019 7:12 am
Forum: General Discussion
Topic: [18650] rechargeable battery + super capacitor
Replies: 7
Views: 250

Re: [18650] rechargeable battery + super capacitor

How long is n seconds, and how much can the voltage drop without causing a problem? Then use RC time constant formula for the capacitor size. 110mA to 160mA seems heavy. Does the raspberry have a low current mode (memory maintained, real time runs, no IO or LEDs etc)? Because 5mA to 10mA (or less) w...
by dyarker
Wed May 01, 2019 4:18 am
Forum: General Discussion
Topic: TV lacking remote control...
Replies: 13
Views: 1087

Re: TV lacking remote control...

Once had a TV that turned on from ON/Off, channel change and volume change etc. So on your set with bad module; (guessing) any signal would turn it on, but with code modulated on the signal garbled it could do nothing else.

Cheers,
by dyarker
Wed Apr 17, 2019 3:06 pm
Forum: General Discussion
Topic: Having a problem with a triac
Replies: 10
Views: 664

Re: Having a problem with a triac

12VAC to 24VAC like you said before? Or, 230VAC as diagram shows? I do not like "pulling teeth" to get info. A page I found via Google says you can trigger by DC. While transistor is on TRIAC remains triggered. Turn transistor off, TRIAC is also off. (or reverse, depending if you put transistor as c...
by dyarker
Wed Apr 17, 2019 3:33 am
Forum: General Discussion
Topic: Having a problem with a triac
Replies: 10
Views: 664

Re: Having a problem with a triac

?????
goal??
schematic of what have done so far?
by dyarker
Tue Apr 16, 2019 6:52 pm
Forum: General Discussion
Topic: Having a problem with a triac
Replies: 10
Views: 664

Re: Having a problem with a triac

Triggering on both half cycles? (positive and negative) Triggering on only one will cut by half. Every pass through zero turns TRIAC off.

Cheers,
by dyarker
Tue Apr 16, 2019 8:05 am
Forum: General Discussion
Topic: Having a problem with a triac
Replies: 10
Views: 664

Re: Having a problem with a triac

With 12VAC applied, what do you expect the result to be?
by dyarker
Wed Mar 13, 2019 4:09 am
Forum: General Discussion
Topic: Any integrated circuit that works as the old tone decoder but for RF ?
Replies: 7
Views: 520

Re: Any integrated circuit that works as the old tone decoder but for RF ?

haklesup, make that 2.4GHz for Wi-Fi.

Cheers,

Also, 118MHZ to 137MHz is for air traffic control.