PA Speaker Line Test Circuit

Guys I need to make a simple circuit to test 100V speaker lines. The speaker line has 10-20 speakers (100V/6W speakers).

Going to use NE555. Please tell comments or modifications to my circuit.

Hy Suraj143,

With your circuit you will be asking the 555 to deliver 12A/8 Ohms= 1.5A. This will either blow the output stage of the 555, which can only supply 200mA, or overheat the 555 and destroy it.

You have two choices.

(1) Put a 56 Ohm resistor in series with the transformer which will generate around 320 mW.

(2) Design a different circuit which can drive the transformer at 12V.

It would be better in any event to drop the 555 supply voltage to 5V.

You will also need a couple of catching diodes on the output.

spec

What do you want to test? A PA system uses an amplifier. Use the amplifier with an input signal to test the speaker lines.

Guys I made the circuit.The problem is the output is very low.How to increase the output power?Need to do this with very limited parts

Suraj143 said:

Guys I made the circuit.The problem is the output is very low.How to increase the output power?Need to do this with very limited parts

Click to expand...

You need an audio amplifier with a powerful output transformer to drive the 100V line. Usually a PA system has the amplifier. The 555 circuit simply produces a low power square wave that sounds like a buzzer. It can feed the audio amplifier.

What test are you trying to do? Continuity? Voltage drop? Impedance? .....?

Since he said Speaker Lines (many of them?) instead of line (singular) then I think he needs to test which line goes where, or if a line has no speakers on it (why not use an ohmmeter then?).