Electronic siren circuits  using   transistors
Alarm systems
The siren circuits are what importance in various alarm system. For example, the emergency alert, burglar alarm circuits, Fire alarm circuits, Timer , sensor controls, etc. Today I would like to introduce the simple and economical simple siren circuits. It is suitable for beginners. My son will gradually build this circuit onto the PCB layout. Look at below! 4 Circuits.
Simple 5V 1A Switching regulator by IC LM2575-5.0
Power supply
The switching regulator which used LM2575-5.0 in this page. You can make the stable voltage by using the 3 terminal regulator like LM317. However, because the output electric current and the inputted electric current are the same approximately, the difference between the input electric power (The input voltage x The input electric current) and the output power (The output voltage x The output current) is consumed as the heat with the regulator. Because it is, the efficiency isn’t good. Data sheet for LM2575 SIMPLE SWITCHER 1A Step-Down Voltage Regulator Source : https://www.interq.or.jp/japan/se-inoue/e_ckt22.htm https://www.national.com/pf/LM/LM2575.htm Related Links 5V power supply using lm2575 …
Christmas Tree Lights Flasher with 7812+LM380
Basic Circuits
This is Circuit Christmas Tree Lights Flasher with 7812 for supply regulator and IC LM380 for Signal generator dirve relay on-off the lamp two set. detail other see circuit. The Christmas Tree Lights Flasher Circuit. It is Lamp flasher that interesting by use IC LM380 for Oscillator generator model Pulse Osc. Low Frequency for use relay switch give Lamp 220V. A lot of get for the accuracy of the circuit then must use IC 7812 DC voltage REG 12V And R1 use fine winking speed of all light bulb. The detail is other see in the circuit better sir. Table …