AC 220V siren circuit using transistors
This AC 220V siren circuit is a simple siren that use 220V AC as power supply. It is small size and use a piezo speaker cause use low power and saving.
Simple audio alarm circuit using transistors
I like to build simple audio alarm circuit using transistors. Although it is old circuit, it still useful. It uses just two transistors, other components.
Make Police siren circuit using 555 timer, transistors and OP-Amp
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 [...]
Simple train whistle circuit using NE556
This is a simple train whistle circuit. We have many ways to generate a two-tone sound circuit. I love to collect a basic or small circuit. This circuit may be…
Free 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 [....]
Two tone alarm with LM3900
This is two tone alarm use op-amp IC, LM3900 (Quad Amplifiers). It produces the frequency of square wave in 2 level. It is high frequency and low then mix the…