0
What economical device - varistor - transistor etc can you use to supply power to a relay until the voltage drops to 10.5 volts?
Wiki User
∙ 14y ago
A zener diode, a transistor, a rectifier diode, and a few resistors. A 10.5V zener diode will conduct until the voltage across it drops to below 10.5. If the relay is small enough, a zener diode is all you need. However, more than likely the current draw of the coil would burn the zener out. Use the zener to drive a transistor, and use the transistor to trigger the relay. V+ | |_______________________ | | _|_| _____|___ |/ \ 10.5V | | /___\ | 3 Relay | __|__ 3 Coil | / \ 3 0---------- /___\ 3 | | | 3 \ \ 4.7K | | / 2.2K / |____ ___| \ \ | / / | | | B | / C | |________|/ | |\ 2N2222 | | \ | | E |______________________| | _|_ \\\ When the voltage is above 10.5V the zener will conduct ant turn on the transistor. The transistor will power the relay. When the voltage drops below 10.5V the zener will stop conducting, shutting off the relay. The rectifier diode absorbs transients caused by the field breakdown in the coil, protecting the transistor. Just a plain resistor will do it or you may follows suggestion and use a computer to do that. The last time i used those ancient devices i find out they operate as a current device like minimum pull in current source. So a passive resistor in series will insure the minimum pull in source however it could be higher then the 10.5 v you need.The above designi just plain silly.
Wiki User
∙ 14y ago
Add your answer:
Earn +20 pts
What is bjt and jfet?
BJT is Bipolar junction transistor FET is Field effect Transistor It is a current controlled device It is voltage controlled device
What is FET?
FET is abbreviation of Field Effect Transistor. This is a transistor in which current is controlled by voltage only and no current is drawn. It is a high input impedence device and is used in computers, telecommunication and control circuits. This transistor is better in certain parameters as compared to BJT, that is Bipolar Junction Transistor.
Transistor is a linear or non linear circuit element?
it is not a passive device .y because it is used to amplify the voltage and current .so as according to the definition of active device is the device which is used to amplify the current r voltage .hence transistor is a active device.
Difference between bjt and ujt?
UJT is the voltage controlled device.in which only one mejority carriers are responsible for current flowing. UJT is one junction transistor and it is three terminal emitter and two base. BJT is the current controlled device. in which both mejority and minority carrier are responsiblefor current flowing. this type of transistor consists of two junction and three terminal these are : emitter , base , collector.
Is a Resistor a nonlinear device?
It is a linear device if it is not a wire wound resistor. These become non linear to AC at high frequencies because of their inherent inductance.
What is bjt and jfet?
BJT is Bipolar junction transistor FET is Field effect Transistor It is a current controlled device It is voltage controlled device
What is FET?
FET is abbreviation of Field Effect Transistor. This is a transistor in which current is controlled by voltage only and no current is drawn. It is a high input impedence device and is used in computers, telecommunication and control circuits. This transistor is better in certain parameters as compared to BJT, that is Bipolar Junction Transistor.
Transistor is a linear or non linear circuit element?
it is not a passive device .y because it is used to amplify the voltage and current .so as according to the definition of active device is the device which is used to amplify the current r voltage .hence transistor is a active device.
Is BJT is a current control device or voltage control device?
transistor is a current controlled device. as the current flows through the base of the transistor , it works like a close switch.
Did varistor having polarity how you will place the component and how you will check the component status?
Varistors are not polarity sensitive. Now I'm pretty sure that the device in question is a varistor. I googled for SAS-820KD05, found several references but unfortunately no data sheet - maybe you have more luck. One main criterium for selecting a varistor is the varistor voltage - as long as the voltage applied to the varistor is below the varistor voltage, it will behave like a capacitor. When the voltage is above, e.g. caused by a transient, it acts as a resistor, shorting this transient. Another important value is the max. pulse current a varistor can withstand.
What is transistor as a switch?
transistor is a nonlinear device. it will acts as a swicth based on the cut in voltage we can easily identifying the the transistor is in forward or reverse bias.in forward it is 'on' reverse bias 'off'.
Why transistor is not used as a transformer?
transistor is switching device - no converting that input vales transformer is converting like step up/down that in voltage values
Why transistor is named so?
What?In May 28, 1946, a survey conducted by Bell Labs offered “a discussion of some proposed names”Among them was "transconductance/transfer varistor".So the question repeats the common mistake that it was "transfer resistor".
Why the transistor is not used in switching 'AC voltage'?
The transistor is a "single direction current flow" device. Typically, for an NPN device, the collector must be more positive than the emitter for the device to bias on. You could use the transistor in an AC circult, but it would only conduct on half the cycle.
Difference between bjt and ujt?
UJT is the voltage controlled device.in which only one mejority carriers are responsible for current flowing. UJT is one junction transistor and it is three terminal emitter and two base. BJT is the current controlled device. in which both mejority and minority carrier are responsiblefor current flowing. this type of transistor consists of two junction and three terminal these are : emitter , base , collector.
What is controlled voltage?
RPS is only the voltage& power controlled device. it can only used for set the input for our wish A device which can change its output according to the voltage supplied to it is called a voltage controlled device.ex. a voltage controlled current source,or a field effect transistor. In a voltage controlled current source the output current changes as the voltage supplied to it changes.
What is the significance of operating point in transistor?
Basically, a Q-point of any device gives information about the operating current & voltage of that particular device..This would help us to know about the max. & min. current or voltage upto which the can be operated safely.
