Not with a schematic because a JPG file type makes a schematic look very fuzzy. A schematic should be saved as a GIF or PNG file type which makes it look extremely clear.

Thanks for the information.

 

yes thanks, I'll start saving in .gif or .png

 

I would like for some reviews on this schematic, and corrections, and please keep in mind the switches and leds are non moveable. I want the relays to be energized when the switches are closed and if one switch opens the relay does the same, I have a 12v supply with battery back up so power failure is not a problem I posted as a .PNG

 

I would like for some reviews on this schematic, and corrections, and please keep in mind the switches and leds are non moveable. I want the relays to be energized when the switches are closed and if one switch opens the relay does the same, I have a 12v supply with battery back up so power failure is not a problem I posted as a .PNG

As I pointed out in my previous post, your relay will turn ON when any switch opens, not OFF as you specified. That is, it would if your input circuitry were correct.
You need to do it as in the attachment.

Note that you don't actually need gates with true and complement outputs. I just used them because they were available in LTspice. Also, where I showed 5 input gates, you can use 8 input gates. LTspice doesn't have an 8 input OR or NOR.

 

Your 100 sec delay also looks like it needs some help.

 

Just so it's been covered; you must not leave any INPUTS to a 4000-series CMOS device "floating" (unconnected); they must have a current path to either Vdd (V+) or Vss (GND).

If you leave any inputs floating, you WILL have problems!

Unused OUTPUTS do not have to be connected.

 

Just so it's been covered; you must not leave any INPUTS to a 4000-series CMOS device "floating" (unconnected); they must have a current path to either Vdd (V+) or Vss (GND).

If you leave any inputs floating, you WILL have problems!

Unused OUTPUTS do not have to be connected.

Yeah, considering the symbols I used appear to have unused inputs, I should have mentioned that.

 

I would like for some reviews on this schematic, and corrections, and please keep in mind the switches and leds are non moveable. I want the relays to be energized when the switches are closed and if one switch opens the relay does the same, I have a 12v supply with battery back up so power failure is not a problem I posted as a .PNG

1. As commented by others, your input connections are wrong. The 1K resistor should be connected to +12V instead. You can use my previous circuit or Ron's(better but requires one extra resistor per channel).

2. The 741 time delay does not has a power supply connected.

3. I purposely choose to energise the relay when switch is open to save energy and extend the life of relay. What is your reason of continuously energising the output relays instead of energising them only in alarm state?

4. You'll need some additional switching to prevent the alarm from sounding when people are home and windows/doors are opened.

 

I will work off ron's Schematic and as far as the relays a closed circuit is harded to tamper with than an open circuit. I am going to parallel a switch to each of the others to by pass if needed, as far as the interior switches they are mainly to monitor my children as they only connect to a buzzer, not a siren

 

this is where I got my 100 sec delay from http://users.otenet.gr/~athsam/relay_timer_switch.htm and a 100 seconds should give time to exit the residence

 

3. I purposely choose to energise the relay when switch is open to save energy and extend the life of relay. What is your reason of continuously energising the output relays instead of energising them only in alarm state?

This is pretty typical in industry. If there is a failure or break anywhere, the relay's solenoid becomes de-energized, and the contacts to the alarm are made (closed).

 

I would do the 100 second delay like this.

To rephrase what SgtWookie said, if you have unused gates in a package, and/or unused inputs on a gate that is used, connect OR/NOR inputs to GND and AND/NAND inputs to Vcc.

 

This is pretty typical in industry. If there is a failure or break anywhere, the relay's solenoid becomes de-energized, and the contacts to the alarm are made (closed).

What happens when the transistor throws a short circuit? How can it be monitored? Which is more likely, a transistor goes short or a relay become open circuited?

There is a difference between monitoring the integrity of a circuit loop and the operation of a device. The relay in this case is NOT in a loop that can be tempered.

I have a relay installed remotely and I am monitoring the relay coil and the connecting cable continuously without the need of energizing the relay.

 

Ron will the 4071's work for each input, not just the delayed, if so I will get the order going, takes about 2 weeks to get, I order fron Bankok, also the caps in the timer circuit, I selected the 50V polar elect, correct? and what do you recommend for the PNP's? I have BC557B on hand.

 

What I'm hearing is you want a AND function with transistors. NOR is easy, that is open collector.

Wouldn't it be easier to make a AND gate (even if it is with diodes) and then drive one transistor?

 

I am looking for a gate (about 20 of them) to de-energize a relay, I am looking to use Ron H's first example of the 4 on page 3 of this post. if one switch is open of the 20 the relay de-energizes.

 

I think I agree after looking at the truth table for a AND gate how can this be done with diodes, if 1n4148 will work have 250 on stock here and it appears so 75V @450ma so I guess next question is how to calcuate the resistor

 

I think I agree after looking at the truth table for a AND gate how can this be done with diodes, if 1n4148 will work have 250 on stock here and it appears so 75V @450ma so I guess next question is how to calcuate the resistor

If you are driving a PNP, you need an OR gate. You can use diodes to make an OR gate. I already went through that mental exercise. Be aware that diodes have no gain, and they shift the logic levels, so you may have difficulty getting your PNP to turn off.
Someone suggested you need AND gates. I would like to see a circuit that uses positive logic AND gates to accomplish this function.

 

this is why I ask ron, I am trying to learn, back to what I asked on page 4, any input about the 4071's working for each input, not just the delayed, and what do you recommend for the PNP's? I'm sure the 50v polar caps will work

 

this is why I ask ron, I am trying to learn, back to what I asked on page 4, any input about the 4071's working for each input, not just the delayed, and what do you recommend for the PNP's? I'm sure the 50v polar caps will work

Re: My AND gate comment, others mentioned this.
The 4071 will work anywhere an OR gate is specified. If you need less than 4 inputs, or more than 4, you can use another CD4000-series OR gate, but you might just want to standardize on one part number. Note that you can cascade ORs indefinitely, as long as speed is not an issue, to get a "wider" input. For example, if you wanted a 100 input OR gate, you could hypothetically use 25 4-input ORs, cascaded into 7 4-input ORs, cascaded into 2 4-input ORs. This is not necessarily the minimum chip count method.
I don't think you mentioned the relay coil current requirement (or, alternately, the coil resistance). We need to know that before we can specify a transistor and the base resistor value.
Note that I inadvertently omitted the 100k pullups on the inputs (in parallel with the LED-resistor combos) in the 555 delay circuit. You need this across every LED-resistor combo to ensure a good logic level when a switch opens.