Tag Archives: basic electr

Power-On Time Delay Relay

Schematic Diagrams      Comments Off on Power-On Time Delay Relay

From : http://ourworld.compuserve.com/homepages/Bill_Bowden/ Here’s a power-on time delay relay circuit that takes advantage of the emitter/base breakdown voltage of an ordinary bi-polar transistor. The reverse connected emitter/base junction of a 2N3904 transistor is used as an 8 volt zener diode which creates a higher turn-on voltage for the Darlington connected… Read more »

Regulated Power Supply by Transistor (TIP31)

Schematic Diagrams      Comments Off on Regulated Power Supply by Transistor (TIP31)

circuit Regulated Power Supply by Transistor (TIP31) This is simple dc power supply circuit. That use transistor be important equipment perform boost up current give the power goes up. By have the zener diode formed control voltage be stable the character Regulated base. By this circuit can give voltage 9… Read more »

Powerful Siren by BC337

Schematic Diagrams      Comments Off on 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 800mA NPN Transistor SW1___________SPST Toggle or Slide Main Switch (See… Read more »