Why doesn't this circuit work with a newer relay? Answered
I have a riddle I hope someone here can answer. I have a circuit that is supposed to flash a light and sound a buzzer at the same time. I have two versions of the circuit. One is from probably the 70's or 80's and one is current. they are wired as shown in the picture. The one built in the 80's flashes the light and rings the buzzer as designed. Unfortunately I don't have the 80's component with me so I cannot read the resistance of the coil. I don't have the part number of the relay. So a quick rundown of what I know about the two.
Relay: part number unkown
Coil resistance: unknown
Capacitor: 12v 1000uF
Flashes once every second or so.
Coil resistance: 960 ohms according to printing on relay
Capacitor: 16v 1000uF
Flashes once when power is applied the relay just buzzes light glows dimly. however if the light is removed and the wire goes straight to ground the circuit operates and the relay opens and closes
I realize there isn't much here to go on. So a little more about the story. As I said I don't have the original relay part number and when I did, I searched for a datasheet. Every search came up with the replacement part number (R40-11D2-12). I cannot seem to locally source a 12v 1000uF capacitor that is of the same physical dimensions. A 16v 1000uF is about the same size as the original.
My thought is that there are only two culprits possible here. The newer relay coil has too much or too little resistance therefore not allowing the cap to charge. Or the cap cannot properly charge because of it's specs. Or both. Being that the circuit operates properly with the light removed and wired straight to ground it makes me suspect there is too much resistance somewhere. I know there are other ways of doing this however the results are not exactly the same. Is there a way to do this as is with current parts?