Heavens Tbilisi! 'A while!' I will presume a coupla seconds like you are shorting out the current limiter on a bypass cap. 'Turns on' is also problematic if you don't specify after being off for at least so-and-so period. I will further presume your excitation is DC. You hook up a RC string across the supply. The tap goes to one of the inputs of a voltage (hate that word!) comparator. The other input is a reference, like a backwards Zener (or coupla LEDs, even) with a ballast R, maybe, say 2/3s Vcc. Timing cap charges, changing potential at the tap, comparator triggers Q which fires relay. Comparator has provisioning to avoid the jits, such as Schmidt action. Alternatively, Norton comparator with input resistors.
If you need more time, one option is a capacitance multiplier circuit.
Yes, sorry for saying 'A While', I did mean just a few seconds. Its for speaker protection circuit put in my amp. Because of that loud THUMP sound I get when the power goes directly on.
Hi Nick, For the purpose of delaying the connection of speakers to the amplifier I would forget about the "delay on make" modules that I previously recommended and instead use a 555 timer connected to a mechanical relay as Don and others have advised. The delay on make module can delay the closing for up to 17 minutes but if all you need is a couple seconds the 555 timer and appropriate RC network will be best. Also the mechanical relay will give you a hard connection of the speaker line while the delay on make module always has a voltage drop accross its connection.
Hi Nick, For the purpose of delaying the connection of speakers to the amplifier I would forget about the "delay on make" modules that I previously recommended and instead use a 555 timer connected to a mechanical relay as Don and others have advised. The delay on make module can delay the closing for up to 17 minutes but if all you need is a couple seconds the 555 timer and appropriate RC network will be best. Also the mechanical relay will give you a hard connection of the speaker line while the delay on make module always has a voltage drop accross its connection.
