transforman
26-07-12, 19:32
Βρήκα στο Internet ένα απλό ηλεκτρονικό κύκλωμά που είναι σαν μετρητής.
Το κύκλωμα αυτό βασίζεται στα PNP transistors, θα ήθελα όμως αν ξέρει κάποιος να το ξανά σχεδιάσει αλλά με NPN transistors.
107154
Q1, Q2 - Any good PNP switching transistor
S1 - Reed switch
C1 - 220uF Electrolytic
R1 - 100k Micrco Potentiometer
R2 - 1/4 watt 1k
SC1 - 200volt 6 amp SCR
This is a very simple, yet effective timer based on a basic RC charging circuit. It will time for an interval of about 3 seconds up to about 20 seconds based on battery voltage used and components used. R1 sets how long the timer runs. For longer times, a larger capacitor can be substituted for C1. Any voltage up to about 12 volts should work fine with this circuit, although I have only tested it up to 9 volts. S1 is the trigger for the timer to start. The timer will start when S1 opens (it is normally closed). As long as S1 is closed, Q1 is saturated, reverse biasing Q2 and turning it off. When S1 opens, C1 begins charging through R1 and Q1. When it is fully charged, there will be no more base-emmiter current and Q1 will turn off. This will allow current to flow through R2 to the base of Q2, saturating it and turning SC1 on.
Το κύκλωμα αυτό βασίζεται στα PNP transistors, θα ήθελα όμως αν ξέρει κάποιος να το ξανά σχεδιάσει αλλά με NPN transistors.
107154
Q1, Q2 - Any good PNP switching transistor
S1 - Reed switch
C1 - 220uF Electrolytic
R1 - 100k Micrco Potentiometer
R2 - 1/4 watt 1k
SC1 - 200volt 6 amp SCR
This is a very simple, yet effective timer based on a basic RC charging circuit. It will time for an interval of about 3 seconds up to about 20 seconds based on battery voltage used and components used. R1 sets how long the timer runs. For longer times, a larger capacitor can be substituted for C1. Any voltage up to about 12 volts should work fine with this circuit, although I have only tested it up to 9 volts. S1 is the trigger for the timer to start. The timer will start when S1 opens (it is normally closed). As long as S1 is closed, Q1 is saturated, reverse biasing Q2 and turning it off. When S1 opens, C1 begins charging through R1 and Q1. When it is fully charged, there will be no more base-emmiter current and Q1 will turn off. This will allow current to flow through R2 to the base of Q2, saturating it and turning SC1 on.