Comments on: Police siren

By: Srinivasan.E

Srinivasan.E — Thu, 12 Jan 2012 13:15:10 +0000

I am ece dep . I need small project topics.

By: seetharaman

seetharaman — Tue, 08 Nov 2011 19:33:25 +0000

Hi Shinoj if you want your battery to get drained fast you can remove on/off switch. No other component can removed from the circuit if want it to function.

By: Shinoj

Shinoj — Mon, 07 Nov 2011 13:09:08 +0000

Can i remove the on/off switch from the circuit

By: seetharaman

seetharaman — Sat, 05 Nov 2011 17:29:11 +0000

Hi Shinoj by removing the push switch you cannot produce the raising lowering sound effect in the tone of sound.

By: Shinoj

Shinoj — Fri, 04 Nov 2011 13:29:32 +0000

Can i remove the push button from this circuit

By: seetharaman

seetharaman — Wed, 19 Oct 2011 17:29:53 +0000

Hi Shinoj BEL100P, 2N2907, CK100, SK100, 8550, BD136, BD138, BD140 BC327 etc

By: Shinoj

Shinoj — Mon, 17 Oct 2011 16:50:48 +0000

Please tell another pnp transistor replacing the transistor Q2 2N3702

By: Seetharaman

Seetharaman — Sat, 18 Jun 2011 17:25:26 +0000

Hi Abdullah S2 should be on. when S2 is (call-bell push type), pushed the capacitor gets charged, oscillation frequency increases in, while you release S1 the capacitor discharges and the frequency reduces, giving siren effect. once the siren work is over with S1 it can be switched off.
(S1 is regular on / off switch.

By: Abdullah

Abdullah — Sat, 18 Jun 2011 09:19:05 +0000

“When the switch S1 is released the C1 will discharge and the transistor Q1 will become OFF slowly.”
Is it S2 releasing or S1?

By: charles chalo

charles chalo — Fri, 25 Mar 2011 13:40:53 +0000

posting of electronic project circuits on my email address.