3 Police siren circuits using 555 timer
This is police siren circuit using 555 IC, with PCB layout, using 2 IC-555 as frequency oscillators and transistor to drive sound to the speaker […] Read more
Alarm sounds
4 ideas of tone generator circuit using FET, SCR, transistors
This is simple Warble tone generator circuit , use scr as main of oscillator and signal will be boost, then feedback to SCR again. Output is 32 ohms speaker [….] Read more