Book Light

Description A simple book light Schematic Bill of materials QTY PART-REFS VALUE CODE --- --------- ----- ---- Resistors --------- 1 R1 150K 1 R2 120R 2 R3,R4 100K Capacitors ---------- 1 C1 10nF 1 C2 220uF Transistors ----------- 1 Q1 NPN 1 Q2 PNP Diodes ------ 1 D1 3V Bulb Miscellaneous ------------- 1 BAT1 3V 1 SW1 Push Button switch

Basic DC PSU

This is a basic DC power supply using the 78XX voltage regulator. Schematic Parts List QTY PART-REFS VALUE --- --------- ----- Capacitors ---------- 1 C1 1000uF 1 C2 100uF Integrated Circuits ------------------- 1 U1 78XX Miscellaneous ------------- 1 BR1 BRIDGE RECTIFIER 1 FU1 3A Fuse 1 TR1 TRAN-2P2S - 115v primary / 24 v secondary

LM317 Basic example

This is the most basic example of using a LM317 voltage regulator. The variable resistor (R1) and R2 are used to select the output voltage. The Lm317 is capable of delivering up to 1A of output current depending on the type you have.The input voltage can be up to 40V and output voltage can be adjusted from 1.2V to 37V. In our example we recommend 28v max. A heat sink must be fitted to the LM317 where the output current exceeds 250 milliamps. Bill of materials QTY PART-REFS VALUE --- --------- ----- Resistors --------- 1 R1…

Flashing led circuit

Description A simple LED flasher using a 555 timer Schematic Bill of materials Resistors --------- 2 R1,R3 1k 1 R2 470k Capacitors ---------- 1 C1 1uf Integrated Circuits ------------------- 1 U1 555 Diodes ------ 1 D1 DIODE-LED

Fundamental Digital Gates

There are 5 basic digital gates used to perform Logic Operation and these are called a Buffer, NOT, AND, OR, XOR Basic Logic Gates Symbol Mathmatical Formula Truth Table Buffer Q = A A Q 0 0 1 1 NOT Q = NOT A A Q 0 1 1 0 AND Q = A . B A B Q 0 0 0 0 1 0 1 0 0 1 1 1 OR Q = A + B A B Q 0 0 0 0 1 1 1 0 1 1 1 1 XOR Q = A + B A B Q 0 0 0 0 1 1 1 0 1 1 1 0

SMD resistors

All surface mount resistors have a 3-digit or 4-digit code. Here is a picture of a 3-digit surface mount resistor The first and second figures indicate the significant figures and the third one, is the multiplier. As an example, if the SMD resistor has the figures 102, it indicates 1, 0 = 10 x 102 ohms. That is the value is 1K. This next example can catch people out at first , 100 is not in fact a 100 ohm resistor but is in fact a 10×100 = 10 ohms or 10×1 = 10 ohms. In the case of resistors less than 10 ohms, the…