A sort of silly circuit

Sno-o-o-o-ort >:-} ...Jim Thompson

For energy efficiency, there are also latching relays (two coils, and a permanent magnet); slightly more expense, but unbeatable hold current minimization. It takes two pins from the microprocessor to drive, though.

You don't need two MCU pins to drive a single-coil latching relay. One pin, a buffer, and a series cap will do it. (Of course the cap has to be fairly big.)

One trick I like is to add a non-latching form-C relay with its coil in a d iode bridge and its contacts in series with the coil of the latching relay. That allows bootstrapping out the coil-contact capacitance of the latching relay, since the coil is isolated except during switching.

This costs some operating margin, so you need to use, say, 9V coils with a

Cheers

Phil Hobbs

At those low coil currents the contacts can break without the relay dropping out.

True.

You are snorting a lot lately. You should see a doctor and find out what's wrong.

On Sunday, December 27, 2015 at 3:53:42 PM UTC-5, John Larkin wrote:

.com wrote:

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a minimum

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ent method leaves no immunity against vibration.

Snorting is healthy, and latching relays have effectively infinite gain as far as I'm concerned.

That being the case, here's my 555 version.

D1 .---+---[5k]---|-+-----|RST | | _)|| | | | === | [5k] | | === | | | '-||--|cv | 10uF | Vcc GND| '---------' | | +5V ===

Version 4 SHEET 1 1208 680 WIRE 400 16 368 16 WIRE 512 16 464 16 WIRE 640 16 592 16 WIRE 368 64 368 16 WIRE 368 64 272 64 WIRE 400 64 368 64 WIRE 512 64 480 64 WIRE 640 64 640 16 WIRE 640 64 512 64 WIRE 976 64 640 64 WIRE 272 112 272 64 WIRE 272 112 240 112 WIRE 304 112 272 112 WIRE 304 128 304 112 WIRE 624 128 576 128 WIRE 1136 128 848 128 WIRE 240 144 240 112 WIRE 576 144 576 128 WIRE 512 192 512 64 WIRE 624 192 512 192 WIRE 1136 192 1136 128 WIRE 240 240 240 208 WIRE 272 240 240 240 WIRE 304 240 304 208 WIRE 304 240 272 240 WIRE 272 256 272 240 WIRE 368 256 368 64 WIRE 624 256 368 256 WIRE 976 256 976 64 WIRE 976 256 848 256 WIRE 976 288 976 256 WIRE 1136 304 1136 272 WIRE 512 320 368 320 WIRE 624 320 512 320 WIRE 880 320 848 320 WIRE 368 352 368 320 WIRE 880 368 880 320 WIRE 976 368 976 352 WIRE 512 448 512 320 WIRE 592 448 512 448 WIRE 880 448 880 432 WIRE 880 448 672 448 WIRE 368 464 368 432 FLAG 1136 304 0 FLAG 576 144 0 FLAG 976 368 0 FLAG 368 464 0 FLAG 272 256 0 SYMBOL voltage 1136 176 R0 SYMATTR InstName V1 SYMATTR Value 5 SYMBOL ind 288 112 R0 SYMATTR InstName L1 SYMATTR Value 1H SYMATTR SpiceLine Rser=167 SYMBOL schottky 256 208 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D1 SYMATTR Value 1N5817 SYMATTR Description Diode SYMATTR Type diode SYMBOL Misc\\NE555 736 224 R0 SYMATTR InstName U1 SYMBOL res 496 48 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 10k SYMBOL cap 864 368 R0 SYMATTR InstName C1

SYMBOL cap 960 288 R0 SYMATTR InstName C2 SYMATTR Value 10nF SYMBOL voltage 368 336 R0 WINDOW 3 24 96 Invisible 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V2 SYMATTR Value PULSE(0 5 5mS 20nS 20nS 300mS) SYMBOL res 688 432 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 5k SYMBOL res 608 0 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 5k SYMBOL diode 400 32 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D2 TEXT 680 400 Left 2 !.tran 350m

No, it's not optimized. Yes, it needs a reset diode.

Hahahahahah! (Merry Christmas!)

Cheers, James Arthur

Troublemaker!

You can do anything with a 555 timer >:-}...

...Jim Thompson

Oops, forgot the timing cap...

D1

I think it can be done with HC logic and r's and c's, total 5 parts if the drive timing is controlled, 6 parts if not.

Yes, but is it a 74HC555?

(I almost went 'hc, but what sort of man can swim against pin 3's 200mA current? Not to mention the cool-factor.)

('hc Schmitt-triggers are some of the most wonderful things ever made.)

Cheers, James

th-a-reset-controller-IC

The classic solution is to use a latching relay.

Doesn't his circuit on the 555 thread meet that test? Two IC's and an R-C. Four parts, IIRC.

Cheers, James Arthur