Transistor vs Relay

Thread Starter

Goerijoe

Joined Mar 25, 2018
5
Hi I have a project that will be necessary to turn 1.5 volts into 6 volts to power a 6v electric actuator. The actuator amperage consumption is unknown but will be minimal (it has a small gear reduction motor) I was initially thinking about using a relay but it's been hard to find a 1.5v relay. Can I use a transistor instead of a relay? How would I go about doing this? Thanks.
 

AlbertHall

Joined Jun 4, 2014
11,217
Certainly you can use a transistor to switch 6V power to the motor using a 1.5V signal for control. Something like shown below, the transistor type and resistor value depending on how much current the motor needs. The motor should have a reverse diode across it to protect the transistor, anode to the transistor collector.
1583140955382.png
 

ericgibbs

Joined Jan 29, 2010
12,456
hi G,
It is as the circuit in post #3, no special name.
Low side driver, means the load is in the collector to supply, you must add a suppression diode across the motor in order to protect the transistor when switching an inductive load.
E
 

BobaMosfet

Joined Jul 1, 2009
1,629
Certainly you can use a transistor to switch 6V power to the motor using a 1.5V signal for control. Something like shown below, the transistor type and resistor value depending on how much current the motor needs. The motor should have a reverse diode across it to protect the transistor, anode to the transistor collector.
View attachment 200390
don't foget the snubber diode around the motor to protect the Transistor
 

dl324

Joined Mar 30, 2015
12,786
What do you call this type of circuit with transistor directly switching on the motor circuit?
There's no special name. It's just a transistor being used as a switch.

In the example given, the motor is being driven low side. With a PNP, you'd drive the motor high side. In an H bridge, you'd use pairs of NPN and PNP transistors:
1583177812974.png
 
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