Showing posts with label Counter. Show all posts
Showing posts with label Counter. Show all posts
Tuesday, May 24, 2011
Long Delay Timer Using IC 4011 Nand Gates
This following circuit shows a Long Delay Timer Circuit Diagram. This circuit designed mainly to switch off a portable radio after some time:
A very long time constant is provided by R1 and C1. C1 discharges and the near zero voltage at its positive lead is applied to the high impedance inputs of the four gates of IC1 wired in parallel when P2 is momentarily closed. The battery voltage is available at Q1 Emitter since the four paralleled gate outputs of the IC go therefore to the high state.
The circuit will start if P2 is pushed for 1 to 5 second and will switch off after about 35 minutes. The time delay can be varied depends on values of R1 and/or C1. If required, P1 will stop the timer. LED D1 is optional. When the load is placed far from the time, LED D1 can be useful to signal relay operation
List Components of Long Delay Timer Circuit :
R1 : 10M R2 : 4K7 R3 : 1K C1 : 220µF/25V D1 : LED any type D2 : 1N4148 IC1 : 4011 Quad 2 Input NAND Gate CMos IC Q1 : BC337 P1,P2: SPST Pushbuttons RL1 : 12V Relay Switch
Monday, May 23, 2011
74LS90 Counter With 7 Segment Display
Here is the circuit diagram of a seven segment counter based on the counter 74LS90 IC TTL.This circuit can be used in conjunction with various circuits where a counter to display the progress adds some more attraction. This circuit accepts any TTL compatible logic signal, and can be expanded easily.
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| 74LS90 Counter Circuit With 7 Segment Display |
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| 7 Segment Common anode |
- All pulses to be counted are to be TTL compatible. They should not exeed 5V and not fall below ground.
- You can add more digits by building a second (or third, or fourth, etc...) circuit and connecting the pin 11-6 junction of the 74LS90 and 74LS47 to pin 14 of the 74LS90 in the other circuit. You can keep expanding this way to as many digits as you want.
List Component:
R1-R7 : 470 Ohm 1/4 Watt Resistor
U1 : 74LS90 TTL BCD Counter IC
U2 : 74LS47 TTL Seven Segment Display Driver IC
DISP1 : Common Anode 7 Segment LED Display
Saturday, February 12, 2011
CD40110BE - 4 Digit Up/Down Counter
This is a simple up down counter circuit that can be used of a large number of applications. The circuit is based on the IC CD40110BE which is a CMOS decade up/down counter.
Common cathode seven segment display is connected to the 7-segment output of each IC.Display connected to the IC1 represents the lowest number and display connected to IC4 represents the largest number. Synchronous counting is achieved by connecting BORROW and CARRY pins of the preceding stage IC to the CLK DOWN and CLK UP of the next stage IC. For UP counting trigger pulse must be given to the pin7 of IC1 and for down counting trigger pulse must be given to the pin9 of IC1.The RESET pins of all IC are shorted and they have to be connected to ground during normal operation. Connecting the RESET pins to positive supply using the switch S1 resets the counter.
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