Hello all,
Thanks for being here in advance.
I have put together many H-bridges. Very familiar with the Schematic. Putting one together so far has not been hard at all.
Getting one to work proper is. The one in my hand has 4 2n3904's running it. they are all npn and i see some schematics are
calling for the negative end of the bridge to be pnp. I have tried both was and this seems to be working. However it is very underpowered.
i have:
The Arduino plugged in via usb ---> laptop
The hc-05 plugged into 5v, Rx ---> Tx, Tx ---> Rx
The positive side of bridge feed from 12v seperate supply
All three commonly grounded
Test results.
Arduino output: apprx. 4.5v
Hc-05 input: apprx. 5.1v
Hot rail breadboard: 9.6v
Top left 2n3904. (positive input is north):
C: 9.6
B: 4.5
E: 3.8
Top right:
C: 9.6
B: 0.0
E: .007
Bottom left:
C: 3.8
B: 0.0
E: 0.00
Bottom right:
C: .004
B: 4.5
E: .001
Test point @ DC motor:
-: .005
+: 3.79
325ohm resistors are at each base. germainium dioide from collector to emitter, negative pointing to collector.
All readings where with the H-bridge active and under load. I have no clue... i have a feeling this is somehow related to the fact that the bottom two transistors are not pnp. the only pnp transistors i have laying around are c8550's and im thinking they might not be suitable since they have that 2w audio spec? i have tried using them. acts like a dead short. i have 4 and they all seem ok outside of the bridge. im also thinking it might be the forward voltage/current from the arduino?
Thanks for being here in advance.
I have put together many H-bridges. Very familiar with the Schematic. Putting one together so far has not been hard at all.
Getting one to work proper is. The one in my hand has 4 2n3904's running it. they are all npn and i see some schematics are
calling for the negative end of the bridge to be pnp. I have tried both was and this seems to be working. However it is very underpowered.
i have:
The Arduino plugged in via usb ---> laptop
The hc-05 plugged into 5v, Rx ---> Tx, Tx ---> Rx
The positive side of bridge feed from 12v seperate supply
All three commonly grounded
Test results.
Arduino output: apprx. 4.5v
Hc-05 input: apprx. 5.1v
Hot rail breadboard: 9.6v
Top left 2n3904. (positive input is north):
C: 9.6
B: 4.5
E: 3.8
Top right:
C: 9.6
B: 0.0
E: .007
Bottom left:
C: 3.8
B: 0.0
E: 0.00
Bottom right:
C: .004
B: 4.5
E: .001
Test point @ DC motor:
-: .005
+: 3.79
325ohm resistors are at each base. germainium dioide from collector to emitter, negative pointing to collector.
All readings where with the H-bridge active and under load. I have no clue... i have a feeling this is somehow related to the fact that the bottom two transistors are not pnp. the only pnp transistors i have laying around are c8550's and im thinking they might not be suitable since they have that 2w audio spec? i have tried using them. acts like a dead short. i have 4 and they all seem ok outside of the bridge. im also thinking it might be the forward voltage/current from the arduino?
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