Wednesday, April 26, 2006

Touch Switch


Experiment With NAND Gate - CMOS 4011



Output goes high when touch wires bridge by finger.

Gates Oscillator

Experiment With NAND Gate - CMOS 4011





(CMOS 4011 Layout)


Circuit





Try this super-simple experiment. The output frequency is about 1kHz (square wave).

Wednesday, April 19, 2006

Telephone FM Transmitter


Descrition & Circuit


This project is taken from www.electronics-lab.com.

With some modification, I create my own version of FM Telephone bug complete with stripboard layout.

Theortically, the frequency range is from 88MHz to 94MHz but you may experiment with the coil structure to tune it






Circuit



Strip Board Layout






Parts List














Diode IN4384 4
LED 1
Resistor 12k 1
1k 1
200R 1
Capacitor 470p 1
330p 1
25p 1
12p 1
Transistor A933(PNP) 1
Coil *See note 1

*Coil note

7 or 8 turns of 22AWG(diameter .6mm) around 9/64inch(3.6mm) drill bit. Antenna using the same wire 22AWG, 5inch long


Picture


Compact!





With antenna!



Put it online!



Get ready to tune your radio!



Monday, April 10, 2006

Lab Power Supply


Description and Circuit


Make your own lab power supply complete with adjustable voltage and constant current source.

Using single IC (LM324)

Here is the circuit.




Strip Board Layout.







Part List


1 LM324 Opamp

1 Ammeter 100 µA 1k ohm

1 Voltmeter

6 IN4001

1 Zener Diode 9.1V

1 Full-Wave Bridge Rectifier

1 LED

2 NPN Transistor, 2N3055

1 NPN Transistor, BC109C

1 Transformer

2 E-Capacitor 2200µF

1 Potentiometer 5k ohm linear

1 Potentiometer 10k ohm linear

1 Resistor 500 ohm

2 Resistor 2.2k ohm

1 Resistor 560 ohm

1 Resistor 6.2k ohm

2 Resistor 68k ohm

1 Resistor 0.22 ohm

4 Resistor 4.7k ohm






Component Image.












LM324






2N3055








Some Pictures.