relay circuit

[RKC]

Hello-
I need help in designing a circuit which would take an input from any of 3 momentary switches and then operate a relay.

The relay needs to latch but only after any of the momentary switches have been made for >1sec or the relay will not operate.

it would be helpful if there was an additional switch added to reset the circuit

Preferred voltage is 12V DC.

Thanks
RC

 

[Ralph Mowery]

In article <cc39d0e5-0505-4101-89aa-878d899f25f9@googlegroups.com>,
rk.covell@gmail.com says...

Hello-
I need help in designing a circuit which would take an input from any of 3 momentary switches and then operate a relay.

The relay needs to latch but only after any of the momentary switches have been made for >1sec or the relay will not operate.

it would be helpful if there was an additional switch added to reset the circuit

Preferred voltage is 12V DC.

Thanks
RC

Several ways. One is to use some 555 timmers in each switch to give a 1
second delay. Then use an extra set of contacts onthe relay to go fro
the coil to the power supply. Put another normally closed switch in that
line to break the power and reset the relay. See any standard 3 wire
motor starter circuit.

If the relays draw a small ammount of current, go from the power source
to the switch then put a large value resistor in series and a capacitor
across the coil. When the capacitor charges the relay will pull in. To
seal it in, see above.

 

[M Philbrook]

In article <cc39d0e5-0505-4101-89aa-878d899f25f9@googlegroups.com>,
rk.covell@gmail.com says...

Hello-
I need help in designing a circuit which would take an input from any of 3 momentary switches and then operate a relay.

The relay needs to latch but only after any of the momentary switches have been made for >1sec or the relay will not operate.

it would be helpful if there was an additional switch added to reset the circuit

Preferred voltage is 12V DC.

Thanks
RC

_
/ \
GND-(- +)o--o--------------o------------o
\_/ >| |
2N2907 |-o-o |
12V /| | |
| | |
| | |
.-. | |
10k | | o |
| | .o.10k | \
'-' | | | o o
| | | o)|
220 Schottky diode o '-' )|
___ | | _)|
OFF (Grd) oo|___|--|<o--------o | o------o
| | | Your Relay(12 DC type)
| | o
___ | | |/
On (+12) o--------o|___|o----o----oo--o| On 2N2222
| |>
220k | |
o |
--- ===
100uf --- GND
|
|
===
GND
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)


220R on Diode time constant set to you shouldn't need a flyback diode
on rlay, but you can put one there if you wish.

 

Il giorno mercoledĂŹ 1 febbraio 2017 19:12:48 UTC+1, RKC ha scritto:

Hello-
I need help in designing a circuit which would take an input from any of 3 momentary switches and then operate a relay.

The relay needs to latch but only after any of the momentary switches have been made for >1sec or the relay will not operate.

it would be helpful if there was an additional switch added to reset the circuit

Preferred voltage is 12V DC.

Thanks
RC

use a stupid microcontroller.
It would be less than 100 lines of C code.

Bye Jack

 

On Wednesday, February 1, 2017 at 1:12:48 PM UTC-5, RKC wrote:

Hello-
I need help in designing a circuit which would take an input from any of 3 momentary switches and then operate a relay.

The relay needs to latch but only after any of the momentary switches have been made for >1sec or the relay will not operate.

it would be helpful if there was an additional switch added to reset the circuit

Preferred voltage is 12V DC.

Thanks
RC

"use a stupid microcontroller.
It would be less than 100 lines of C code. "

....and about 1/10 the price.

 

Il giorno giovedĂŹ 2 febbraio 2017 16:35:58 UTC+1, sdey...@hotmail.com ha scritto:

On Wednesday, February 1, 2017 at 1:12:48 PM UTC-5, RKC wrote:
Hello-
I need help in designing a circuit which would take an input from any of 3 momentary switches and then operate a relay.

The relay needs to latch but only after any of the momentary switches have been made for >1sec or the relay will not operate.

it would be helpful if there was an additional switch added to reset the circuit

Preferred voltage is 12V DC.

Thanks
RC

"use a stupid microcontroller.
It would be less than 100 lines of C code. "

...and about 1/10 the price.

if it's a one time thing, probably buying an Arduino and some shield with connectors and relays will not be the cheaper solution, but definitely the faster.

Bye Jack

 

On Wednesday, February 1, 2017 at 1:12:48 PM UTC-5, RKC wrote:

Hello-
I need help in designing a circuit which would take an input from any of 3 momentary switches and then operate a relay.

The relay needs to latch but only after any of the momentary switches have been made for >1sec or the relay will not operate.

it would be helpful if there was an additional switch added to reset the circuit

Preferred voltage is 12V DC.

Thanks
RC

A PIC16F690, 5v reg, a transistor, some vector board.
Or $5.25 Arduino from Ebay & a transistor.

 

[Benderthe.evilrobot]

"RKC" <rk.covell@gmail.com> wrote in message
news:cc39d0e5-0505-4101-89aa-878d899f25f9@googlegroups.com...

Hello-
I need help in designing a circuit which would take an input from any of 3
momentary switches and then operate a relay.

The relay needs to latch but only after any of the momentary switches have
been made for >1sec or the relay will not operate.

it would be helpful if there was an additional switch added to reset the
circuit

Preferred voltage is 12V DC.

A real minimalist dodge is the unijunction transistor.

They're probably getting hard to find - next in line is the programmable
unijunction transistor, which is basically a thyristor with the gate at the
wrong end.

The PUT is also getting rare these days, but the complementary assymetry of
the 4-layer device means you can turn the circuit upside down and use a low
power SCR like the 2N5061.

You need a bleed resistor across the timing capacitor to leak the charge
away when the button isn't pressed, the circuit produces a narrow pulse
suitable for tripping a latch.

 

[M Philbrook]

In article <mNrmA.636879$La3.223563@fx38.am4>,
Benderthe.evilrobot@virginmedia.com says...

"RKC" <rk.covell@gmail.com> wrote in message
news:cc39d0e5-0505-4101-89aa-878d899f25f9@googlegroups.com...
Hello-
I need help in designing a circuit which would take an input from any of 3
momentary switches and then operate a relay.

The relay needs to latch but only after any of the momentary switches have
been made for >1sec or the relay will not operate.

it would be helpful if there was an additional switch added to reset the
circuit

Preferred voltage is 12V DC.

A real minimalist dodge is the unijunction transistor.

They're probably getting hard to find - next in line is the programmable
unijunction transistor, which is basically a thyristor with the gate at the
wrong end.

The PUT is also getting rare these days, but the complementary assymetry of
the 4-layer device means you can turn the circuit upside down and use a low
power SCR like the 2N5061.

You need a bleed resistor across the timing capacitor to leak the charge
away when the button isn't pressed, the circuit produces a narrow pulse
suitable for tripping a latch.

using a SCR is the simplest thing to do...
Put NC switch in series with it to open the circuit.
a NO switch to apply some gate current with a RC network to get a
delay on.

Senstive SCR's work well for pulling in a relay coil ...

 

[Benderthe.evilrobot]

"M Philbrook" <jamie_ka1lpa@charter.net> wrote in message
news:MPG.330416b9b97ae55f98a006@news.eternal-september.org...

In article <mNrmA.636879$La3.223563@fx38.am4>,
Benderthe.evilrobot@virginmedia.com says...

"RKC" <rk.covell@gmail.com> wrote in message
news:cc39d0e5-0505-4101-89aa-878d899f25f9@googlegroups.com...
Hello-
I need help in designing a circuit which would take an input from any
of 3
momentary switches and then operate a relay.

The relay needs to latch but only after any of the momentary switches
have
been made for >1sec or the relay will not operate.

it would be helpful if there was an additional switch added to reset
the
circuit

Preferred voltage is 12V DC.

A real minimalist dodge is the unijunction transistor.

They're probably getting hard to find - next in line is the programmable
unijunction transistor, which is basically a thyristor with the gate at
the
wrong end.

The PUT is also getting rare these days, but the complementary assymetry
of
the 4-layer device means you can turn the circuit upside down and use a
low
power SCR like the 2N5061.

You need a bleed resistor across the timing capacitor to leak the charge
away when the button isn't pressed, the circuit produces a narrow pulse
suitable for tripping a latch.

using a SCR is the simplest thing to do...
Put NC switch in series with it to open the circuit.
a NO switch to apply some gate current with a RC network to get a
delay on.

Senstive SCR's work well for pulling in a relay coil ...

Essentially; the SCR variant of the PUT circuit I suggested is exactly
that - but its applied more intelligently to get repeatable, predictable
delay period.