Powerful Siren by BC337

Parts: R1,R3____________1K 1/4W Resistors R2,R5___________10K 1/4W Resistors R4_____________220R 1/4W Resistor R6_____________220K 1/4W Resistor R7______________22K 1/4W Resistor R8_____________100K 1/4W Resistor C1,C2___________22µF 25V Electrolytic Capacitors C3______________10nF 63V Polyester or Ceramic Capacitor C4______________47µF 25V Electrolytic Capacitor Q1,Q2_________BC557 45V 100mA PNP Transistors Q3____________BC337 45V Continue reading

555 Timer/Oscillator Tester

Source : http://www.uoguelph.ca/~antoon/circ/555test.htm 555 Timer/Oscillator Tester by Tony van Roon Description 555 Tester: The 555-tester above is basically a led flasher circuit but with the 555 removed. Imagen the output being a square-wave pulse with a high and low pulse, and Continue reading